In a large saucepan melt butter, stir in flour, mustard, pepper and allspice. Add milk; cook and stir for 6-7 minutes or until thickened and bubbly. Remove from heat. Stir in cheese until melted. Beat egg yolks; stir in about 2 tablespoons of the cheese mixture. Return all to the cheese mixture in the saucepan. Stir in Indiana Kitchen ham; set aside.