Thaw the puff pastry and sorrel. Drain excess water from the sorrel and chop it. Peel the onions. Wash and dry the parsley. Prepare the remaining ingredients. Preheat the oven to 180°C.
Grate the cheese on a coarse grater.
Melt the butter in a frying pan and fry the onions over medium heat for 5-7 minutes until golden and translucent.
Break three eggs into a deep bowl and whisk.
Add chopped sorrel, cottage cheese, grated cheese, chopped parsley and fried onions to the bowl.
Salt and pepper the filling to taste. Stir.
Roll out the puff pastry to a thickness of 3-4 mm. Line a baking pan with parchment paper and grease with vegetable oil. Place the puff pastry into the pan, forming sides.
Place the filling on top of the dough and distribute evenly.
Place the pie in the oven for 30-40 minutes. Cool the finished pie slightly and remove from the mold.
Garnish the pie with fresh chopped spinach. Bon appetit!