Step 1: Prepare the crust

Mix flour and salt in a bowl. Rub in the cold butter with your fingertips until the mixture resembles coarse crumbs. Add cold water, one tablespoon at a time, until the dough just comes together. Do not overwork it.

Step 2: Chill and shape

Shape the dough into a disc, wrap it, and refrigerate for 20–30 minutes. Roll it out on a lightly floured surface and fit it into a 9-inch (23 cm) tart or pie pan. Trim the edges and prick the base with a fork.

Step 3: Blind-bake the crust

Heat the oven to 190°C (375°F). Line the crust with parchment paper and fill with pie weights or dry beans. Bake for 15 minutes, remove the weights and paper, then bake for another 5–7 minutes until lightly dry. This helps prevent a soggy bottom.

Step 4: Cook the spinach

Heat olive oil or butter in a skillet. Cook the onion for 3–4 minutes, if using. Add garlic and cook for 30 seconds. Add spinach and stir until wilted. Let it cool slightly, then squeeze or drain away excess liquid.

Step 5: Make the egg mixture

Whisk eggs, milk or half-and-half, salt, pepper, paprika, and nutmeg. Stir in the cheddar and mozzarella, reserving a small amount of cheese for the top if desired.

Step 6: Assemble

Spread the spinach mixture evenly in the baked crust. Pour the egg and cheese mixture over it. Gently shake the pan to distribute the filling. Do not fill above the pastry rim.

Step 7: Bake

Bake at 180°C (350°F) for 30–40 minutes, until the edges are set and the center has only a slight wobble. If the crust browns too quickly, cover the edges loosely with foil. The center should reach 71°C (160°F) for an egg dish.

Step 8: Rest and serve

Let the quiche rest for 10–15 minutes before slicing. Serve warm or at room temperature with a green salad, roasted vegetables, or fresh tomatoes.