Heat oven to 400 degrees.
Remove 1 package of Puff Pastry from freezer (each package contains 2 sheets). Thaw the Puff Pastry sheets for 45 minutes.
Shred 2 cups of Gruyere cheese with a cheese grater and tear 1 3 oz. package of prosciutto into pieces.
Unfold both sheets of Puff Pastry once they have slightly thawed. Lightly flour a flat surface and roll them out slightly with a rolling pin. Do not roll them out completely. Simply roll out the creases in the pastry sheets.
Pierce each piece of Puff Pastry with a fork 10-12 times. This will prevent the pastry from 'puffing' as it bakes and will allow the pinwheels to stay together.
Add 1/2-3/4 cup of shredded Gruyere cheese to each pastry sheet. Place half of the prosciutto pieces on each pastry sheet. Make sure the cheese and prosciutto reaches the edges of each pastry sheet.
Roll each of the pastry sheets tightly into a 'log' shape.
Cut each pastry sheet into 12-14 slices (each slice should be 1/2").
Spray baking sheet with cooking spray.
Place each of the slices cut side down onto a baking sheet. (Can bake in 2 batches or all at once with 2 separate baking sheets).
For egg wash:
Beat 1 egg and 1 Tbsp. of water in a small bowl. Brush each pinwheel with egg wash.
Place the baking sheet in the oven and bake for 16-18 minutes or until tops are nice and golden. Remove pan when finished baking.
Let cool and place on serving tray. Garnish with the zest of 1 lemon.Mince 1/2 cup or so of basil or fresh herb of choice. Sprinkle pinwheels with minced herbs.