Remove the frozen puff pastry from the fridge and let it thaw until pliable. Roll it out into a 10x12-inch rectangle.

Spread 1.5 tablespoons of Dijon mustard evenly across the pastry surface, leaving a 0.5-inch border.

Layer 6 slices of deli ham over the mustard, sprinkle 1 cup of grated Gruyère or cheddar cheese over the ham.

Roll the pastry from one long edge, forming a tight log. Trim the ends and wrap in plastic wrap, refrigerate for 20 minutes.

Repeat with the second sheet of puff pastry: roll, spread mustard, layer ham and cheese, roll, trim, wrap, and refrigerate for 20 minutes.

Preheat your oven to 375°F (190°C) and line two baking sheets with parchment paper.

Unwrap the logs, cut into 0.5-inch slices, and arrange them on the prepared baking sheets.

Bake for 18 minutes, or until the pinwheels are puffed and golden brown.

Sprinkle with freshly chopped parsley before serving warm.