In a skillet melt butter. Saute onions and mushrooms and set aside. In a bowl, combine uncooked sausage, sage, majoram, allspice and egg yolk. Mix well. Add turkey and onion mixture. Combine two rolls and flatten into an 8-inch circle, prepare 6 circles. Divide turkey mixture evenly between the circles. Fold dough over filling and pinch ends together. Place pinched-side down on a large sprayed baking sheet. Brush with beaten egg white. Place 3 whole sage leaves on top, if desired, and brush again. Bake at 375 degrees F. for 30-35 minutes or until golden brown.