Unroll dough, and separate into 4 rectangles; press seams to seal.
Combine mayonnaise and mustard; spread over rectangles, leaving a 1/2-inch border. Sprinkle ham and cheese evenly over half of each rectangle; moisten edges with water. Fold dough over, and pinch edges to seal.
Bake at 375° for 10 minutes or until puffed and golden.
Note: Baked Hamwiches may be frozen in an airtight container up to 1 week.