In a skillet, pour the olive oil on a medium heat then add the minced onion, garlic, salt, black pepper and red pepper flakes, stir from time to time until the onion softens ( You can go further and caramelized the onion if you like).
2 tablespoon olive oil, 2 cloves garlic, 1 onion, ¼ teaspoon salt, ⅛ teaspoon ground black pepper, pinch of red pepper flakes
Add the spinach to the skillet in batches if you use a small skillet then stir until the spinach becomes wilted.
300 g spinach
Next, Spread the spinach mixture in an ovenproof 14x24 cm baking dish, set aside.
In a medium-sized bowl, crack the eggs then add the heavy cream and whisk together until combined.
8 eggs, ¼ cup heavy cream
After that, add mozzarella and cheddar cheese to the eggs, stir well.
1 cup cheddar cheese, 1 cup mozzarella
Pour the eggs over the spinach in the baking tray. Bake for 20-25 minutes.
Garnish with chopped parsley (optional) and serve immediately.
Notes
I recommend using fresh spinach for better texture.
I highly recommend sauteing onion, garlic and fresh spinach before adding them to the quiche to prevent it from getting soggy.
To Store: Store the leftovers in an airtight box in the fridge for a couple of days; you can also freeze it if you want. Either way, it heats well in the microwave or oven.