Heat oven to 400 degrees.
Remove the rough ends of the asparagus.
Place the olive oil and asparagus into a bowl. Add the oil and salt to the asparagus and toss well to coat.
Spray the inside of a 10×10 baking pan (or whatever baking pan that fits the puff pastry) with canola oil. Place the sheet a puff pastry in the inside of the baking pan.
Top the puff pastry with a layer of all the parmesan cheese and then a layer of all the mozzarella cheese.
Place the asparagus evenly across the puff pastry. Top with additional small amount of mozzarella if desired.
In a small bowl place the egg and whisk it to create an “egg wash.” Lightly coat the edges of the puff pastry with the egg wash.
Place the baking pan into the oven and cook for 40 minutes at 400° or until the edges are golden brown. Remove the tart from the oven.
Zest the lemon evenly over the tart. Serve immediately with or without freshly grated parmesan cheese.