-
1
Preheat oven to 350F (180C).
-
2
Prepare a 8 inchsquare baking pan with cooking spray and flour.
-
3
To prepare chocolate peanut butter swirl, melt the chocolate chips and peanut butter in a small saucepan over low heat, stirring often until smooth.
-
4
Remove from the heat; let cool while preparing the crumbs and batter.
-
5
To prepare crumbs, combine the flour, brown sugar, margarine, and peanut butter in a mixing bowl until the mixture forms crumbs.
-
6
Remove 3/4 cup (tightly packed) of the mixture and set aside.
-
7
To prepare cake, add egg whites, milk, vanilla, baking powder, and baking soda to the remaining crumbs in the mixing bowl until thoroughly moistened.
-
8
Spread half of the batter in the prepared pan; gently streak half of the chocolate peanut butter mixture over the top.
-
9
Repeat with the remaining batter and chocolate peanut butter mixture.
-
10
Scatter the reserved crumbs over the top, pressing them in gently so they adhere to the batter.
-
11
Bake for about 50 minutes or until crumbs and top of the cake are firm.
-
12
Cover the pan loosely with aluminum foil, if the cake is getting too dark during baking, loosely cover it with a piece of aluminum foil.
-
13
Let the cake cool in the pan on a wire rack for 15 minutes.
-
14
Loosen around the sides of the pan, then carefully invert onto the rack and turn right-side-up.
-
15
Cool completely before serving.
