In a large heavy saucepan, combine 1/2 cup butter, sugar, cocoa and vanilla; cook and stir until butter is melted. Stir a small amount of hot mixture into egg; return all to the pan, stirring constantly. Cook and stir until mixture thickens, about 5 minutes. Stir in crumbs and coconut. Press into a greased 9-in. square pan.
In a small bowl, beat remaining butter until smooth. Add milk, pudding mix and confectioners' sugar; beat until fluffy. Spread over crust. Refrigerate until firm, 1-1/2 to 2 hours.
In a microwave, melt chocolate chips and butter; stir until smooth. Cool. Spread over pudding layer. Chill until set. Cut into bars. Yield: 4 dozen.