1 1/2 cups all-purpose flour
1 cup white sugar
1 egg
1 teaspoon baking powder
1 teaspoon baking soda
1/4 teaspoon salt
1 1/2 cups mini semisweet chocolate chips
1 1/4 cups chopped walnuts
Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9x13 inch pan.
In a large bowl, combine flour, sugar, egg, baking powder, baking soda and salt. Mix well. Fold into the chocolate mixture, mixing just until combined. Spread over the prepared pan.
Bake in preheated oven for 25 to 28 minutes, or until a toothpick inserted into the center of the cake comes out clean. Cool completely on a wire rack, cutting into squares or rectangles, then layer with mini chocolate chips. Cut the remaining chocolate into squares. Pour filling into the prepared pan.
Bake in the preheated oven for 10 to 12 minutes, or until springs begin to release and a toothpick inserted into the center of the cake comes out clean. Cool completely before frosting. Frost with chocolate glaze.