Place the pie crust into a pie dish and press it gently. Trim extra edges if needed. Use a fork to poke small holes at the base. This helps the crust bake evenly and stay crisp.

Heat butter in a frying pan over medium heat. Add chopped onion and cook until soft. Add spinach and cook briefly until wilted. Remove from heat and let it cool slightly.

In a mixing bowl, crack the eggs and whisk well. Add heavy cream, salt, and black pepper. Mix until smooth and light. This mixture will create a soft and creamy quiche texture. If you enjoy egg-based dishes with a similar creamy richness, a ham and cheese egg custard baked in a shell is another gorgeous variation worth trying.

Spread the cooked onion and spinach evenly over the crust. Add cooked bacon or chicken pieces on top. Sprinkle shredded cheese evenly to create layers of flavor.

Slowly pour the egg mixture over the fillings. Make sure it spreads evenly across the crust. This helps all ingredients cook together perfectly.

Preheat the oven to 180°C. Place the quiche in the oven and bake for thirty-five to forty minutes. The top should look golden, and the center should be set.

Remove the quiche from the oven and let it rest for ten minutes. This helps it set properly. Slice gently and serve warm for best taste.