Cut each pastry sheet into fourths and roll each square slightly thinner so there is room for the meat and cheese.

Add 3 slices of ham, 1 slice of cheese (folded in half), and a squirt of mustard (smeared) to half of each square. Then brush a whisked egg on the edges of the half of the square with meat and cheese, so you can fold over the top and seal the edges.

Fold over the top half of the dough and pinch the edges or crimp them with a fork to seal the dough together. Place pockets on a parchment or silicone lined baking sheet. Cut a few slits on top of each pocket with a knife for ventilation, and then brush the tops with the whisked egg.

Bake at 400 degrees Fahrenheit for 15 to 25 minutes. Make sure you peek underneath the pockets to check that the puff pastry is brown, and not doughy. The dough should rise and get flakey. The time will depend on how juicy the ham is and if it leaks out of the pocket while baking. Serve hot.