Cream butter adding 1 egg yolk and 1 cup sugar until all 3 are used. Add fruits, nuts and vanilla. Mix well. Line bottom of greased 9 x 9 inch pan with vanilla wafers. Pour 1/2 filling mixture into pan and spread over wafers. Add another layer of vanilla wafers and the rest of the filling. Place in freezer at least 3 hours. Serve in squares topped with whipped cream if desired.