Preheat the oven to 375° F. Grease an 8x8-inch baking pan with cooking spray.
On a lightly floured surface, unroll dough and separate the sheet into rectangles. Pinch the perforations to seal. Spread Dijon mustard onto each rectangle. Top with sliced ham and cheese. Starting with one short side, roll up each rectangle. Pinch edges to seal. Cut each roll into 5-6 slices. Place cut side up in baking pan.
In a small bowl, whisk together melted butter, garlic powder and parsley. Brush over pinwheels, then sprinkle poppy seeds on top. Bake for 15-20 minutes, until the rolls are golden.
