In a large bowl, beat eggs until foaming.

Cook spinach according to package directions.

Drain the cooked spinach in a strainer and press out excess liquid.

In a 10-inch skillet, cook finely chopped onion in olive oil until wilted (about 5 minutes).

Stir cooked spinach and sautéed onion into the beaten eggs.

Add diced ham, Parmesan cheese, and Ricotta cheese to the egg and spinach mixture.

Season with salt and pepper to taste.

Line a 10-inch pie plate with half of the pie pastry.

Pour the spinach mixture into the pastry-lined pie plate.

Cover with the remaining pie pastry.

Cut 6 (1-inch) vents in the top pastry to allow steam to escape.

Seal and flute the edges of the pie crust to create a decorative border.

Bake in a preheated oven at 375°F (190°C) for 35-40 minutes, or until the crust is golden brown and the filling is set.