Line an 8x8-inch or 9x9-inch baking pan with parchment paper. Coat paper with a splash of toasted sesame oil.
In a large pot, melt 6 tablespoons butter over medium heat. Continue cooking, swirling pan occasionally, until butter solids start to brown, about 4 minutes.
Reduce heat to low and stir in 2 tablespoons sesame seeds and cook 1 minute.
Add remaining 2 tablespoons butter and 12 ounces marshmallows and cook, stirring constantly, until marshmallows begin to melt, about 3 minutes.
Stir in ⅓ cup black sesame tahini, 2 tablespoons honey, ¾ teaspoon salt and ½ teaspoon vanilla; continue cooking just until marshmallows are fully melted.
Off heat, stir in 6 cups rice krispie cereal to coat.
Transfer rice krispie mixture to prepared pan and lightly press into an even layer. Avoid pressing too hard or packing too tightly. Cool at room temperature for 30 minutes before cutting into 9 squares.
Store in an airtight container or resealable zipper-lock bag for up to 1 week.