Heat oven to 350°F (176ºC) with rack set in middle position. Coat an 8½ × 4½-inch loaf pan with nonstick spray. Line pan with parchment paper, leaving a 2-inch overhang on two sides; coat paper with nonstick spray.
Whisk together flour, baking powder, and salt in a large bowl, set aside.
Whisk together eggs, honey, oil, yogurt, lemon zest, lemon juice, and lemon extract until smooth. Add liquid mixture to flour mixture and stir until mostly incorporated but some pockets of flour remain.
Toss blueberries with 1 teaspoon flour to coat; fold blueberries into the batter just until combined. Scrape batter into prepared pan and smooth top.
In a small bowl, combine oats, turbinado sugar, and melted butter; sprinkle evenly over batter. Transfer pan to oven and bake until top of bread is golden brown and a toothpick inserted in the center comes out clean, 55–60 minutes, rotating halfway through baking.
Let bread cool in pan on wire rack for 15 minutes, then turn bread out on to rack to cool completely.
Store bread wrapped in parchment paper (I just use the paper from baking) and foil at room temperature for up to 3 days, though it’s best within 2 days. If you need to store it longer, pop it in the refrigerator for up to 5 days.