Thaw the puff pastry according to package instructions or make the rough puff pastry. 2 sheets puff pastry
Roll out the pastry until it is considerably thinner (⅛") then cut each sheet into 4 squares.
To half of each square (note they will be folded into triangles), add 1 teaspoon of Dijon, then 1 tablespoon shredded cheese, 1-1½ oz ham, and another tablespoon of cheese. Leave one centimeter of space around the filling to seal.
1/4 cup dijon mustard, 8-10 oz virginia ham, 8 oz aged cheddar cheese
Lightly wet the exposed edge around the filling with a swipe of water, then fold the puff pastry over top of the fillings. Use your fingers to press the dough together to seal it.
Repeat the process for the remaining puff pastry squares, then use the tines of a fork to press down on the pastry edges to seal it completely.
Add the turnovers to baking sheets lined with parchment paper (you can also add them to the sheet to assemble), then refrigerate the turnovers for 15-30 minutes.
Preheat the oven to 400°F/205°C while the turnovers chill.
Before baking, whisk together one egg with 1 teaspoon of water, then brush it over top of each turnover. 1 large egg
Use the tip of a sharp knife to cut 3-4 small slits into the pastry to allow steam to escape, then sprinkle on fresh thyme leaves. fresh thyme
Bake the turnovers for 15-20 minutes until deeply golden, then serve immediately.