Preheat the oven to 375º.
Dice the onion into small pieces and mince the garlic. Cook both in a small skillet with 1 tablespoon of olive oil over medium heat until soft and transparent (about five minutes).
While the onions and garlic are cooking, prepare the rest of the filling. In a bowl combine the cottage cheese, parmesan cheese, eggs, salt, pepper, and nutmeg. Mix well.
Before adding the spinach, strain it in a colander and press out as much moisture as possible (squeezing handfuls in a fist works well too).
Once the onions have softened, add them to the cheese/egg mixture along with the squeeze dried spinach. Stir until well combined.
Dust a clean work surface with flour and unfold a sheet of puff pastry onto it. Using a rolling pin, roll the puff pastry into a 12 inch by 12 inch square. Drape the rolled dough over a standard 9 inch pie dish.
Spread the spinach filling evenly inside the pastry lined pie dish. Fold the corners of the pastry back over top of the filling. It’s okay if they do not fully reach to meet each other. If desired, brush a whisked egg over the top (this will give the surface a glossy appearance after cooking).
Bake the pie for 45 minutes in a preheated 375 degree oven. Allow the pie to rest for about 5 minutes before cutting to allow the filling to set.