Preheat oven to 350 degrees. Sift flour, cocoa, baking soda and salt onto wax paper. Beat butter, sugar, eggs and vanilla in a medium-size bowl with electric mixer until fluffy. Stir in dry ingredients; beat until smooth. Fold in half cup of the chopped nuts. Pour into greased 13x9x2 inch pan. Bake in preheated 350 degree oven for 30 minutes. Remove pan from oven to wire rack; sprinkle with peanut butter chips. Let stand about 5 minutes, then spread evenly with a small metal spatula. Sprinkle with remaining nuts, patting down gently. Cool; cut into bars Recipe By :