Ingredients
3/4 cup butter1-1/2 cups sugar1/2 cup baking cocoa3 large eggs, room temperature3/4 cup all-purpose flour1/2 cup chopped walnutsCHOCOLATE CHIP LAYER:1/2 cup butter1 cup packed brown sugar1 large egg, room temperature1 cup all-purpose flour1/2 teaspoon baking soda1 cup semisweet chocolate chips
Preparation
Preheat oven to 350°. Line a 9-in. square baking pan with foil, letting ends extend up sides; grease foil.
In a microwave, melt butter in a large microwave-safe bowl. Stir in sugar and cocoa. Add eggs, 1 at a time, whisking to blend after each addition. Add flour; stir just until combined. Stir in nuts. Spread into prepared pan. Bake 15 minutes.
Meanwhile, for cookie layer, melt butter in another microwave-safe bowl. Stir in brown sugar. Whisk in egg. In a small bowl, whisk flour and baking soda; stir into butter mixture just until combined. Stir in chocolate chips.
Spoon mixture over hot brownie layer. Bake until a toothpick inserted in center comes out with moist crumbs, 35-40 minutes longer. Cool completely in pan on a wire rack. Lifting foil, remove brownies from pan. Cut into bars.
