From: Art of Gluten-Free Baking (http://artofglutenfreebaking.com)
Blueberry Snack Cake, Gluten-Free
-adapted from The Yellow Farmhouse Cookbook by Christopher Kimball
2 cups (290 g) Jeanne’s Gluten-Free All Purpose Flour mix
2 teaspoons double-acting, aluminum-free baking powder
1 teaspoon salt
1 1/4 cups (250 g) granulated sugar
10 tablespoons (140 g) unsalted butter, cold and cut into 10 pieces
2 large or extra-large eggs, separated
1 cup (240 ml) milk
1 1/2 cups (210 g) fresh blueberries (or frozen that have been defrosted, drained, and patted dry)
melted butter and tapioca flour for pan
Preheat oven to 350 degrees F/180 degrees C. Butter and flour at 9 x 13 in pan.
In a large bowl mix together flour, baking powder, salt, and granulated sugar until combined. Add butter pieces and use your fingers to rub them into the flour mixture until they resembled large and small rocks mixed with flour. You can also do this with a pastry cutter or in a food processor.
Remove and reserve 1/2 cup (90 g) of the mixture.
Pour remaining flour mixture into the bowl of a stand mixer fitted with the paddle attachment. Add egg yolks and milk and beat on low to combine and then raise speed to medium and beat for 2 minutes.
While the flour mixture is beating, use a hand mixer to whip the egg whites until they form stiff peaks. After the flour mixture is done beating, remove the bowl from the mixer. Gently fold the flour mixture into the whipped egg whites into the flour mixture.
Spread the batter into the pan and smooth top. Sprinkle the blueberries on top and then sprinkle the reserved crumb mixture on top of all.
Bake for 50 minutes or until a tester inserted into the center of the cake comes out free of crumbs.
Cool in pan set on a wire for about 30 minutes (to allow the cake to set) before serving.
Serve plain or with a side of unsweetened whipped cream