Remove the puff pastry from the fridge about 15–20 minutes before you start if it’s very cold; it should be pliable but still cool. Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.

On a lightly floured surface, unfold the puff pastry sheet. Cut the sheet into 8 squares (4×4) for individual bites, or cut into 4 rectangles for larger portions. Roll gently to an even thickness if needed.

In a bowl, toss together the shredded cheese and chopped rosemary. Add a grind of black pepper. Optionally, add a tablespoon of grated Parmesan for tang.

Place about 2–3 tablespoons of the cheese-rosemary mix in the center of each square, leaving an edge for sealing. If using prosciutto, lay a slice over the cheese before sealing. Brush edges with beaten egg, fold into a triangle or parcel, and seal with a fork. Brush tops with egg wash.

Place pastries on the prepared baking sheet and bake for 12–18 minutes until golden brown and puffed with bubbling cheese.

Let cool for 3–5 minutes on a rack and serve warm with fig jam or salad. For large tarts, slice and serve family style.