On a lightly floured surface, roll out the puff pastry until it’s thin and about 15 inches wide.
Take the puff pastry, leaving a 1-inch border on all sides, top with the proscuitto slices, and sprinkle evenly with cheese. Season with salt.
Starting with the end closest to you, carefully roll the puff pastry up over the filling to create a pinwheel.
Wrap tightly with plastic wrap and refrigerate for 20 minutes.
Preheat the oven to 400°F. Line a baking sheet with parchment paper.
Remove the plastic wrap from the pinwheels, and slice with a serrated knife into 1/4-inch slices. Place each slice on its side on the prepared baking sheet.
Bake for 25-30 minutes until crisp and golden.