Cut and discard the ends of the zucchini. Cut it lengthwise half way through, and then thinly slice it. Place the zucchini slices in a colander/bowl and gently toss with 2 teaspoons of salt. Let it sit for about 30 minutes. This method is called sweating zucchini and it helps to get rid of excess moisture.
Then lightly rinse the zucchini with water and gently squeeze them between your palms in small batches and place them in a clean bowl. Drizzle with olive oil and set aside.
To make the filling:
Now, finely chop parsley and mix it with ricotta. Season with salt and pepper to taste. Alternatively, you can use a small blender to mix ricotta and parsley, and you’ll get a beautiful creamy green filling.
Preheat the oven to 400°F (200°C).
To assemble the tart:
Once the puff pastry is fully thawed, unfold it and lightly roll it into a rectangle. Cut a border about 1/2 inch from the edges without cutting through to create a border. Then score it with a fork all over inside the border.
Transfer it onto a baking sheet lined with parchment paper. And spread the ricotta filling evenly within the border. Then arrange the zucchini slices on top. Repeat with the second puff pastry.
In a small dish, mix egg yolk with 1 tablespoon of water to make an egg wash. Brush the egg wash over the border of the tart.
Bake the tart for 20-25 minutes, or until the crust is puffed up and golden brown. Cool on wire rack for 5-10 minutes before serving.
Note 1: I use and recommend whole-milk ricotta cheese over skim ricotta cheese.Note 2: You can use either flat leaf or curly parsley here.Note 3: 1 box of puff pastry comes with 2 sheets. You can use just 1 sheet and half the rest of the recipe, if you'd like.Note 4: Instead of egg wash, you can also use a tablespoon of heavy cream.