The Unexpected Ingredient That Will Majorly Upgrade Your Spinach Quiche

There's nothing quite like a quiche. This classic dish is perfect for breakfast, brunch, or even dinner, and it's not hard to see why. This tasty egg-based, meal (which is not to be confused with a frittata) is easy to customize, with endless variations depending on your and your guests' tastes.

From crustless quiche to quiche Lorraine and everything in between, there's no shortage of delicious ideas for quiche. Whether you're looking for a hearty meat-filled quiche filled with bacon and sausage or are craving something more vegetable-focused, such as a crustless zucchini quiche recipe, you can find the perfect recipe to suit your tastes. And if you're not quite sure where to start, there's no better way to get inspired than by simply adding some spinach to your quiche.

No matter what kind of quiche you're craving, there is one unexpected ingredient that will make your quiche even better.

For a great spinach quiche, don't hold the onions

Caramelized onion is a key ingredient in many dishes and it's easy to see why. When onions are slow-cooked in butter or oil over low heat, they become sweet and rich, adding depth of flavor to any dish. This simple ingredient can transform your spinach quiche from good to great.

Mashed recipe developer Mackenzie Burgess, RDN, shared her recipe for a succulent caramelized onion and spinach quiche, emphasizing the need to cook the onions slowly in order to achieve the perfect flavor. "You typically won't start to see the browning occur until 8-10 minutes into the cooking process," Burgess says, "so be patient. The extra flavor here is so worth it."

If you're cooking a big brunch and running short on free hands, a relatively hands-off hack for easily caramelizing your onions is to place them on a baking sheet and pop them in the oven. Simply toss the onions in a bit of oil, water, and salt, and they'll caramelize over the course of 40-50 minutes with just the occasional stirring. They can then be added to your spinach mixture. Whether you're looking for something special to impress your guests or just want a tasty way to sneak more veggies into your diet, this extra ingredient is sure to upgrade your spinach quiche.