- Put a rack in the center of the oven and heat oven to 425 degrees. Line a baking sheet with a silicone liner or parchment paper. If you like, you can sprinkle Gruyère or Cheddar onto the center of the liner or paper in an approximate 10-by-13-inch rectangle. - 1/2 cup Gruyere or Cheddar Cheese 
- In a medium bowl, whisk together egg, Parmesan, lemon zest or rosemary, garlic (if using), and pinch of salt and pepper until smooth. Beat in the crème fraîche until smooth. - 1 Large egg, 2 Tbsp Grated Parmesan, 1  tsp Lemon zest or rosemary, 1 Garlic clove, Kosher salt and black pepper 
- On a lightly floured surface, roll out the puff pastry to form a 10-by-13-inch rectangle, about ⅛-inch thick. Transfer the dough to prepared baking sheet. (Place directly on top of the grated cheese, if applicable.) With a sharp knife, lightly score a ¾-inch border around the edges of the puff pastry, making sure not to cut the pastry all the way through. Using a fork, prick the pastry all over inside the border at 1-inch intervals. - Flour for dusting the work surface, 1 package Puff pastry (14 oz) 
- Spread crème fraîche mixture evenly inside the scored border. Arrange vegetables in an even layer, using just enough to cover the surface in one layer. Scatter onion/scallion microgreens and thyme or rosemary sprigs on top. Lightly drizzle with oil, and sprinkle with salt and pepper. - 3/4  cup Creme fraiche or mascarpone, 3 cups Sliced vegetables, 1/2 cup Onion or Scallion Microgreens, 4 Thyme or Rosemary sprigs, Extra virgin olive oil 
- Bake until the pastry is puffed and golden, and the vegetables are cooked through, about 25 to 35 minutes. Transfer the pan to a wire rack to cool for at least 15 minutes before serving. Serve topped with microgreens and accompanied by lemon or lime wedges, for squeezing. - More Roots 'n Shoots Microgreens for serving, Lemon or lime wedges for serving