1-First Step: Prep and mise en place Thaw the puff pastry according to the package instructions. While that thaws, preheat your oven to 200°C (400°F) and line a baking sheet with parchment paper. Grate the cheese and dice the cooked ham into small pieces so they pack neatly into the pastry. Beat one egg in a small bowl for the egg wash, and have 2 tablespoons of Dijon mustard ready if you plan to use it. Keep salt and pepper close by for a light seasoning.

2-Second Step: Cut and portion the pastry On a lightly floured surface, unfold the thawed puff pastry sheet. Using a sharp knife or pizza cutter, cut the sheet into 8 equal squares. For even baking, make each square roughly the same size. If you prefer smaller pockets, you can cut the sheet into 9 pieces; remember that smaller pockets will cook slightly faster.

3-Third Step: Layer the filling On each square, spread a thin layer of Dijon mustard if using. This helps keep the filling moist and adds tang. Add about 1 to 2 tablespoons of diced ham and roughly 2 tablespoons of grated cheese to the center of each square. Season lightly with salt and pepper, remembering that ham and cheese already have some salt.

4-Fourth Step: Fold and seal Fold each square over the filling to form a triangle or fold into a neat rectangle or pocket choose the shape you like best. Press the edges together gently, then run the tines of a fork along the seams to crimp and seal. Good sealing keeps the melty cheese from leaking during baking. For a decorative edge, fold a small edge of pastry over before crimping.

5-Fifth Step: Egg wash and final prep Brush the top of each pocket with beaten egg to produce a shiny, golden crust when baked. Use a light hand; too much egg wash can drip into the pan. If you want to add herbs, sprinkle a little thyme or parsley on top, or press a small pinch of flaky salt for contrast. Place the pockets on the prepared baking sheet with some space between them so they can puff fully.

6-Sixth Step: Bake Place the baking sheet in the preheated oven and bake for 18-22 minutes at 200°C (400°F), or until the pockets are puffed and golden brown. If you made smaller pockets, check at the 15 minute mark. Rotate the pan halfway through baking for even color. The cheese should be melted and the pastry fully puffed.

7-Final Step: Rest and serve Remove the pockets from the oven and let them cool on the baking sheet for a few minutes so the filling sets slightly. Serve warm with a simple green salad, pickles, or roasted veggies. Leftovers keep well and reheat nicely in an oven or toaster oven for a few minutes to bring back the crispiness.