Step 1

Heat oven to 350°F. Grease 13x9x2 baking pan.

Step 2

Combine melted butter, sugar, eggs and vanilla in large bowl; beat well. Add flour, cocoa and milk; beat until blended. Stir in 1 cup nuts. Pour into prepared pan.

Step 3

Bake 25 to 30 minutes or just until edges begin to pull away from sides of pan. Cool completely in pan on wire rack.

Step 4

Melt 1/2 cup butter and peanut butter chips in medium saucepan over low heat, stirring constantly. Add sweetened condensed milk, stirring until smooth; pour over baked layer.

Step 5

Place chocolate chips in small microwave-safe bowl. Microwave at medium (50%) 45 seconds; stir. If necessary, microwave at medium an additional 15 seconds at a time, stirring after each heating, just until chips are melted when stirred. Drizzle bars with melted chocolate; sprinkle with remaining 1/4 cup nuts. Refrigerate 1 hour or until firm. Cut into bars. Cover; refrigerate leftover bars.