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This blueberry rhubarb pie has been tested, and tested, and tested some more. I’ve honed in on the perfect thickener, verified that it can be made with either fresh or frozen fruit, and perfected the flaky pie crust through years of tweaking and testing. Plus, the no-cook filling is the ideal balance of sweet, tart and lightly spiced. Just delicious!
I’ve been writing about food and developing recipes for more than 10 years. And pies are one of my favorite desserts to develop and make. They’re both impressive and rustic at the same time, which is the kind of cooking I love most.
I first learned about using ground tapioca as a pie filling thickener during my internship at America’s Test Kitchen. It’s a longer-lasting, more effective thickener than cornstarch and lets you make a fresh fruit pie without cooking the filling beforehand. Pretty amazing, right?
Let’s dive into making this gorgeous pie!
This recipe article was originally published in April of 2019, it has since been updated with ingredient notes, helpful tips, FAQs, make ahead info, storage and reheating info and a step-by-step video.
Reader Review
Holy cow! Loved how simple it was. Subbed blackberries for some of the blueberries otherwise followed recipe. Totally delicious.
– Tina
Ingredients Needed for Rhubarb Blueberry Pie
Here is a quick rundown of what you’ll need for the recipe. For ingredient amounts, jump down to the recipe card.
- All-purpose flour: for the tender, flaky crust—just don’t over mix the dough!
- Granulated sugar: a few tablespoons are needed for the crust while ¾ cup is used in the filling.
- Kosher salt: every dessert needs a dash of salt. It brings out the flavors and actually enhances the sweetness.
- Vegetable shortening and unsalted butter: the combination of cold shortening and cold butter is ideal for creating a flavorful and flaky crust. Butter brings flavor, fat and moisture, while shortening brings just fat (key for achieving a very tender and very flaky crust).
- Blueberries (fresh or frozen): use ripe, firm fresh berries or frozen (preferably wild because they have more flavor) blueberries. If using frozen, no need to thaw them—just add straight to the filling.
- Rhubarb (fresh or frozen): Make sure you cut it into 1/2-inch pieces so it softens correctly during baking.
- Pure vanilla extract: adds depth and warmth—don’t skip it.
- Lemon zest and juice: enhances the rhubarb tartness and brighten the overall pie.
- Spices: you’ll need freshly grated nutmeg (use your microplane to grate it) and ground cardamom (a little goes a long way but it is spectacular in this pie).
- Quick-cooking tapioca: a powerhouse thickener that keeps the filling juicy but sliceable—make sure you grind it into a powder.
- Egg wash (egg + water): brushed over the crust, it gives your pie a golden, glossy finish.
How to Make Blueberry Rhubarb Pie
This is an overview of the recipe, with a few step-by-step photos to guarantee success. Find the full recipe in the recipe card.
- Make the pie crust and get it chilling in the fridge.
TIP: get a jump start and make this ahead of time. Wrapped in plastic wrap, it can hang out in the fridge for up to 5 days.
- Roll the bottom crust out and carefully transfer it to a pie plate (you can use a regular or deep dish here). Chill it in the fridge while you roll out the top crust.
- Roll out the top crust and either punch vent holes using a cookie cutter, or slice into strips for a lattice top.
- Combine the blueberries, rhubarb, sugar, ground tapioca, lemon, spices, and vanilla together in a large bowl.
TIP: this pie uses tapioca to thicken it. Compared to cornstarch, it has stronger and longer-lasting thickening power, and it creates a glossy filling—not a cloudy filling. You will need a spice grinder or coffee grinder to grind the quick-cooking tapioca pearls into a fine powder. Don’t skip this step!
- Transfer the fruit filling to the dough-lined pie plate and place the top crust on top. Pinch to seal the edges.
- Brush the crust with an egg wash then place in the freezer until the pie dough is firm (if you’re using frozen fruit, skip this step).
- Place the pie on a rimmed baking sheet (so if it bubble over, you don’t have to clean your oven) and bake.
TIP: it’s key to start baking the pie at a high temperature (400ºF) before dropping the temperature (350ºF) for the rest of the bake time. The high temp to start sets the bottom crust and initiates browning—important for creating a crisp, not dense, bottom.
- Let the pie cool completely before slicing and serving. This last set of cooling is important! It allows the molten fruit filling to set. Cut too early and you’ll have a soupy mess.
Rhubarb Blueberry Pie Tips
- Homemade or pre-made pie crust works here. For homemade, it’s important to use a crust that uses both butter and shortening to achieve adequate flakiness.
- Ripe fruit is king. When blueberries and rhubarb are in season, make this with fresh fruit. Out of season, use frozen.
How to Make Rhubarb Pie with Frozen Rhubarb
If you can’t find fresh rhubarb or quality fresh blueberries, frozen is a great option. And surprisingly, using one, or both, of the fruits frozen results in a spectacular pie.
Do not thaw the fruit (too many juices), use it frozen and plan to bake the pie an additional 30 minutes or so at 350ºF.
If the edges of the crust are getting too dark, shield the edges with foil and move the pie to the center rack.
Storage and Reheating Blueberry Pie with Tapioca
I recommend storing this pie, covered with foil, at room temperature for up to 1 day. After that, store it in the fridge for up to 3 days. Reheat the pie in a 300ºF oven, on the lowest rack, until warmed through, 8–12 minutes.
Make Ahead Info
If you want to make this ahead of time, assemble the pie then place in the freezer. Once frozen solid, wrap tightly in plastic wrap and foil. The pie should be baked within 2 months of assembling and freezing.
Rhubarb and Blueberry Pie FAQs
This is a bigger risk for glass pie plates, less of a risk for ceramic pie plates. Use a deep dish ceramic pie plate if you have one. I’ve used both ceramic pie plates and glass pie plates for this pie and have never had an issue. That being said, if your pie plate has a chip in it, do not use it for this recipe. For the safest bet, use a metal pie plate. The only drawback is the crust will likely brown faster than intended. In that case, when you change the oven temp from 400ºF to 350ºF, move the pie from the bottom rack to the middle rack.
I don’t recommend making this swap, but if you are set on doing it, use 3 tablespoons of arrowroot starch.
Instead of looking for tapioca powder, look for quick-cooking tapioca (sold as Minute by Kraft). Then use a spice grinder or coffee grinder to grind it into a powder. If you don’t have a spice grinder, you can also use a blender.
Blueberry Rhubarb Pie
Description
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Ingredients
Flaky Double Pie Crust
- 2½ cups (300g) all-purpose flour
- 2 tablespoons granulated sugar
- 1 teaspoon kosher salt
- ½ cup vegetable shortening, chilled
- 12 tablespoons unsalted butter, cut in ¼ inch pieces, chilled
- 4–6 tablespoons ice water
Blueberry Rhubarb Filling
- 3 cups fresh or frozen blueberries
- 3 cups fresh or frozen rhubarb, cut into ½-inch pieces
- ¾ cup granulated sugar + more for sprinkling
- 2 teaspoons pure vanilla extract
- 1 lemon zested and juiced
- ¼ teaspoon kosher salt
- heaping ¼ teaspoon freshly grated nutmeg
- ⅛ teaspoon ground cardamom
- 2 tablespoons + 2 teaspoons (25g) quick-cooking tapioca
- 1 tablespoon cold unsalted butter, diced
- 1 egg + splash of water, beaten (for egg wash)
Instructions
Flaky Pie Crust
- In bowl of a food processor, combine 2½ cups (300g) flour, 2 tablespoons sugar, and 1 teaspoon salt; pulse to combine.
- Drop dollops of chilled shortening (½ cup) over flour mixture and process until flour resembles coarse cornmeal, about 5 pulses. Sprinkle 12 tablespoons butter over flour mixture and pulse until crumbs are slightly smaller than pea-sized, 15–20 pulses.
- Transfer dough mixture to a large bowl and sprinkle 4 tablespoons ice water over dough.Using a rubber spatula, mix water into dough, pressing the dough together. If the dough doesn’t come together add additional ice water, by tablespoon, and mix until a dough holds together.
- Divide dough into two even halves (a food scale makes easy work of this) and form each into a 4-inch dish. Wrap with plastic, transfer to fridge and chill 1 hour. (Dough can be made up to 3 days ahead of time.)
- Roll one dough disk out into a 12-inch round on a lightly floured surface. Gently transfer dough round to a 9-inch pie plate (deep dish or regular works). Gently ease and press dough onto bottom and up sides, letting excess hang over side. Loosely wrap dough-lined pie plate with plastic and chill in fridge until dough is firm, about 20 minutes.
- Roll second dough disk out into a 12-inch round on a lightly floured surface. Punch out ½–inch holes using a cookie cutter (reserve rounds for decorating, if desired); transfer dough round to a parchment lined baking sheet, cover with plastic wrap and chill 20 minutes.
Blueberry Rhubarb Filling
- Using a spice grinder or coffee grinder, process 2 tablespoons + 2 teaspoons (25g) quick-cooking tapioca into a find powder. Set aside.
- In a large bowl, combine 3 cups blueberries, 3 cups rhubarb, ¾ cup sugar, 2 teaspoons vanilla, grated zest of 1 lemon, 1 tablespoon lemon juice, ¼ teaspoon salt, heaping ¼ teaspoon nutmeg, ⅛ teaspoon cardamom and ground tapioca. Stir until everything is combined.
- Transfer filling to chilled dough-lined pie plate; sprinkle 1 tablespoon butter evenly over filling.
- Gently place second chilled dough round over top of filling (or create a lattice top). Trim overhang to ½-inch then tuck edges under and crimp using thumbs and pointer fingers.
- Brush dough with egg wash; transfer pie to freezer and chill until dough is firm, about 45 minutes (skip this step if using frozen fruit).
- Preheat oven to 400°F (204ºC) with rack set in lowest position.
- Transfer pie to a baking sheet and bake until crust is light golden brown, 25 minutes.
- Reduce oven temperature to 350°F (177ºC), rotate baking sheet, and continue to bake until crust is golden brown, 30 minutes.
- Sprinkle ~2 tablespoons sugar over top of crust and bake until crust is deep golden brown and filling is bubbling, about 30 more minutes. (Keep an eye on the edges—if they're getting too dark, cover edges with a foil sheild.)
- Transfer pie to a wire rack; let cool completely, at least 4 hours.
Notes
Nutrition
This sponsored post is in partnership with Simply Organic and TheFeedFeed. As always the thoughts, opinions, recipe, photos and content are all my own
Yum – that crust looks absolutely delicious. I’m with you- better is always better!
Thanks Emily! 🙂 Love a good crust!
Oh my gosh!!! I love this recipe!!! We go to the Boundary Waters every summer and when we are there wild blueberries are in season. Im totally saving this recipe for our trip. (also, I love blueberry pie and rhubarb pie. I don’t love strawberry rhubarb pie, so I think this is the perfect combo!!!)
No way! We go to Norther MN every year too, love that area. I’ve never had wild blueberries from that area, I will DEFINITELY be seeking them out this year. And I totally agree—blueberry and rhubarb go together MUCH better. I hope you enjoy this one in the summer!
I’ve been drooling over this on Instagram – it’s absolutely beautiful and I cannot wait to make it!
Thanks Tawnie!! It was a favorite at Easter!
Could the tapioca flour get swapped out for arrowroot powder?
I Amber, I think you could definitely use arrowroot powder. I haven’t tested this, but I did some research and if you swap the tapioca out for 3 tablespoons arrowroot powder you should be good! Let me know how it goes!
Yum! I love strawberry rhubarb pie, so this new twist is intriguing! Can’t wait to give it a try!
Yes! The blueberries are a fun addition, and they add such a gorgeous color!
Holy cow! Loved how simple it was. Subbed blackberries for some of the blueberries otherwise followed recipe. Totally delicious.
Hi Tina! I’m so happy to hear it was easy to make and delicious!
Why is the total baking time 85 minutes? 25 @400 degrees, then 30, then another 30? I’m baking it right now and keeping a close eye. Or, did I read that wrong?
Hi Mary, apologies about the confusing timing—we’ve been moving our recipes over to a new recipe card style and sometimes the formatting is impacted. I have updated the recipe to reflect the correct total timing. The pie gets baked at 400ºF for 25 minutes, then gets baked for another hour at 350ºF. We add the sugar to the crust in the last half hour to keep it from browning too early.
I hope that helps!
I’ve never heard of tapioca powder, can I find it in any grocery store? I want to make this delicious looking pie . Thank you
Hi Grace, I apologize for my delay in responding! I recommend buying quick-cooking tapioca (sold as Minute by Kraft) and grinding it in a spice grinder. If you don’t have a spice grinder, you can also use a blender. I hope that helps!