PREP TIME: 15 minutes
COOK TIME: 30 minutes
This light-textured sponge cake becomes a rich indulgence when topped with a creamy, chocolaty frosting.
¾ cup whole-grain pastry flour
½ cup white pastry flour
½ teaspoon baking powder
6 eggs, separated
¾ teaspoon cream of tartar
¾ cup granular sugar substitute
1⁄3 cup unsweetened applesauce
½ cup fat-free milk
1 teaspoon vanilla extract
¼ teaspoon salt
1 cup reduced-fat sour cream
1 cup bittersweet chocolate chips
2 tablespoons granular sugar substitute
1 teaspoon vanilla extract
Heat oven to 325°F. Lightly coat a 9- by 13-inch baking pan with cooking spray.
For the cake: Sift whole-grain and white flours and baking powder into a medium bowl.
In a large bowl, with an electric mixer at high speed, beat egg whites until frothy, about 1 minute. Add cream of tartar and continue beating on high until stiff peaks form, 2 to 3 minutes. Gradually add ½ cup of the sugar substitute and beat until you have a smooth, glossy meringue, about 30 seconds more. Set aside.
In another large bowl, using same beaters, beat egg yolks on high speed for 2 minutes. Add remaining ¼ cup sugar substitute, applesauce, milk, vanilla, and salt; continue beating until mixture is light, airy, and smooth, about 1 minute more. Fold flour mixture into egg yolk mixture just until combined.
Add flour mixture to meringue and gently fold until whites are nearly incorporated. Pour into prepared pan and bake until cake springs back when lightly touched and a tester inserted into center comes out clean, 22 to 25 minutes. Cool in pan on a wire rack.
For the frosting: When cake is cool, combine sour cream and chocolate chips in a small saucepan. Cook over low heat, stirring constantly, until chips are melted and frosting is smooth, about 3 minutes. Add sugar substitute and cook, stirring, until dissolved, about 30 seconds more. Stir in vanilla.
Spread warm frosting over cake and let cool at room temperature until frosting sets, about 1 hour. Cake can remain at room temperature for up to 4 hours.
Makes 12 servings
NUTRITION AT A GLANCE
Per serving: 190 calories, 9 g fat, 4.5 g saturated fat, 6 g protein, 22 g carbohydrate, 1 g fiber, 120 mg sodium
MAKE-AHEAD: Sponge cake can be baked and frosted up to 4 hours ahead. Cover lightly and let sit at room temperature until ready to serve.
TIP Beating egg whites: Eggs separate most easily when cold. However, when beating whites for a recipe, let them come to room temperature first; you get more volume this way. Adding a bit of cream of tartar to the whites helps them reach their full volume; a little lemon juice or vinegar achieves the same thing. Use beaten egg whites immediately; they will lose their volume as they sit.