Adapted from Bon Appetit
Cake:
Nonstick vegetable oil spray
2 large egg whites (1/4 cup)
1/3 cup (packed) golden brown sugar
Pinch of salt
1-1/2 cups coarsely chopped walnuts
1-1/4 cups mini semisweet chocolate chips, divided
2 cups cake flour
1/2 teaspoon salt
1/4 teaspoon baking powder
1/4 teaspoon baking soda
1 cup plus 2 Tablespoons sugar
1/2 cup unsalted butter, room temperature
3 large eggs
3/4 cup sour cream
Topping:
3/4 cup powdered sugar
2 Tablespoons sour cream
Milk
Mix egg whites, brown sugar and salt in a bowl. Mix in walnuts and 1/4 cup chocolate chips.
Sift flour, salt, baking powder and baking soda together in a medium bowl; whisk to fully blend together. Using an electric mixer, beat sugar and butter in a large bowl to blend; about 3 minutes. Beat in eggs one at a time. Stir (do not use a blender) in flour mixture in 4 additions alternately with sour cream in 3 additions, beginning and ending with flour mixture. DO NOT OVERMIX. Stir in 1 cup chocolate chips.
Butter and flour a 10" diameter tube pan, then spray with nonstick spray. Like I said earlier, I used my angel food cake pan, which worked fine. Transfer batter to pan; smooth top.
Spoon walnut mixture evenly over batter. Bake at 350 degrees until a cake tester inserted in the middle comes out clean, about an hour. Cool in pan on rack 10 minutes. Turn cake out onto rack; invert onto second rack (walnuts should be on top). If you use an angel food pan, your cake will already be right side up. Cool. (Can be made one day ahead. Wrap in plastic.)
For the topping, mix powdered sugar and sour cream in bowl, thin to desired consistency with milk, one teaspoon at a time; drizzle over cake.
- Recipe courtesy of Cathy Pollak