2 sticks (1 cup) butter or margerine, room temperature
1 cup packed light -brown sugar
2 large eggs, room temperature
1 tsp. vanilla extract
3/4 cup walnuts, coarsely chopped
Instructions
Heat oven to 350 degrees. Grease a 13 X 9 inch baking pan. Line with foil. Grease foil.
Melt 1 cup chocolate chips in a small bowl in microwave. Heat for 1 minute and stir.
Mix flour and baking powder. In a large bowl, beat butter and sugar with electric mixer until fluffy. Beat in eggs, one at a time, beating well after each addition. Beat in vanilla. Stir in flour mixture until blended. Scoop half of mixture into a second bowl.
Stir melted chocolate into remaining batter until blended. Spread chocolate batter in prepared pan. Drop tablespoons of the plain batter over the chocolate layer. Spread carefully in an even layer. Sprinkle with remaining 1/2 cup chocolate chips and the walnuts.
Bake 30-35 minutes until edges begin to pull away from the sides of pan.
Cool in pan on wire rack before cutting into bars.