3 cups semisweet chocolate chips
3/4 cup butter cut into tablespoons
1 1/2 cups flour
3/4 cup unsweetened cocoa powder
1/2 teaspoon each: baking powder, salt
4 large eggs
1 1/2 cups sugar
2 teaspoons vanilla
3/4 cup creamy peanut butter, but not natural peanut butter
1/2 to 2/3 cups chopped peanuts
1. Heat oven to 375 degrees. Melt 1 1/2 cups of the chocolate chips and the butter in a large saucepan over low heat, stirring constantly; let cool. Combine the flour, cocoa powder, baking powder and salt in small bowl; set aside.
2. Beat the eggs, sugar and vanilla in a large bowl with a mixer on medium speed until combined; gradually add the dry ingredients, beating well. Add the reserved chocolate mixture; beat well. Spread the dough onto a greased 15-by-10 inch rimmed baking sheet; bake until firm, about 12-15 minutes. Cool until barely warm, about 20 minutes.
3. Spread the peanut butter over the chocolate layer; sprinkle with the peanuts. Melt the remaining 1 1/2 cups of the chocolate chips; spread while warm over the nut layer. Let cool completely; cut into squares.
Note: Sue Manos says she microwaves the peanut butter for 5-10 seconds to soften it for spreading.