Preheat the oven to 400° F.
Cover a large baking sheet or 2 medium-size baking sheets with Reynolds Wrap® Non-Stick Foil and set aside.
In a bowl, mix the ricotta cheese with the lemon zest, lemon juice and salt, and set aside.
Slice each puff pastry sheet into four even squares, for a total of eight squares, and place them on top of the parchment paper, leaving a little space between each square. If you are using a large baking sheet, you may only be able to fit six squares. You can either place the remaining two pastries on a smaller baking sheet and bake them at the same time, or bake in two separate batches.
Scoop about 1 1/2 tablespoons of the ricotta mixture and spread it onto a puff pastry square, leaving about a 1-inch border along the edges. Repeat this step for the remaining puff pastry squares.
Top each square with about 1/2 tablespoon green peas and 5 to 7 asparagus pieces.
Sprinkle 1/2 tablespoon of grated parmesan cheese onto each square.
Bake in the oven for 18 to 22 minutes, until the pastry is flaky and golden.