Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper.
Unroll the crescent dough into a large rectangle, pressing seams to seal.
Spread Dijon mustard evenly over the dough.
Layer the ham slices evenly across the dough, then sprinkle with shredded cheese.
Starting at one long edge, roll the dough tightly into a log. Slice into 12 equal pieces.
Place the pinwheels cut-side up on the prepared baking sheet.
Brush the tops with melted butter, then sprinkle with garlic powder and parsley.
Bake for 12–15 minutes, or until golden brown and bubbly.
Let cool slightly before serving.