1. Heat oven to 350 F.
2. In a small bowl, stir together mayonnaise, mustard and sage.
3. Without separating rolls into individual pieces, cut rolls in half horizontally. Remove tops. In a 13x9-inch baking pan, place the roll bottoms.
4. Spread evenly with mayonnaise mixture. Arrange turkey evenly over mayonnaise. Spread cranberry sauce over turkey. Arrange cheese over sauce. Place the roll tops over sliced cheese.
5. Brush top of rolls with melted butter; sprinkle with onion. Bake 10–15 minutes until cheese melts and sandwiches are hot. Let stand 2 minutes.
6. Cut rolls into 12 pieces using a serrated knife. Serve warm.