Spinach & Mushroom Quiche

Nutrition Notes

Are Eggs Healthy?

In the past, eggs were controversial due to their cholesterol content, but now even the American Heart Association says healthy adults can have an egg a day as part of a balanced diet. Eggs are a good source of protein. It's important to note that almost half of an egg's protein is in its yolk, and that's not all. According to the United States Department of Agriculture (USDA), the yolk is also a source of many other nutrients, including iron, vitamin B12 and choline. Two large whole eggs will give you about 13% of your daily vitamin D, per the USDA, a vitamin that is not found naturally in many foods.

Are Mushrooms Good for You?

Mushrooms are filled with earthy goodness, including niacin, a B vitamin which helps the body tap into the energy in the carbohydrates, protein and fats you eat, as well as a bit of plant-based protein, according to the USDA. Mushrooms contain compounds that help support the gut and immune system, reduce the risk of cancer and protect the nervous system according to a 2018 review in Food Science and Human Wellness. A 2023 study in Antioxidants found that mushrooms that are exposed to ultraviolet light can help meet your vitamin D needs. Depending on the brand, a serving could provide up to a full day's worth of vitamin D, which is important because many people are deficient in this vitamin.

Is This Recipe Gluten-Free?

Yes, this recipe is gluten-free (and vegetarian-friendly!).

Tips from the Test Kitchen

I Don't Have a Sweet Onion. Can I Use a Regular Onion Instead?

Sweet onions, such as Vidalia onions, are milder and sweeter than regular onions. They are less pungent due to their high water content and are grown in low-sulfur soil. Since they are naturally sweet, you can eat them raw in salads or sandwiches. If you don't have a sweet onion, you can use a white onion or yellow onion as a substitute in this recipe because they taste milder when cooked.

Can I Use Frozen Spinach Instead of Fresh?

Yes, you can! Frozen spinach is a good alternative to fresh as long as it is thawed and squeezed dry. Wet and watery ingredients will leave you with a wet and watery quiche, which is why we pre-cook the veggies before baking them in the custard. Be sure to squeeze dry or pre-cook any frozen or fresh veggies before adding them to the custard.

I Don't Have Half-and-Half. Can I Use Whole Milk Instead?

Yes, you can use whole milk instead of half-and-half. Because whole milk has less fat content than half-and-half, the quiche will be slightly less creamy, but it won't affect the flavor.

Can I Use a Different Type of Cheese?

Gruyère cheese is a hard cheese from Switzerland with a mild, nutty flavor and creamy texture that melts well. If you prefer, you can substitute Gruyère cheese with another type of shredded cheese, such as Swiss, Gouda or Cheddar.

How to Make Spinach & Mushroom Quiche Ahead

Quiche can easily be made ahead of time or enjoyed as leftovers. To make Spinach & Mushroom Quiche ahead, cover and refrigerate for up to 5 days. Cover and reheat whole quiche at 350°F for 30 to 45 minutes or microwave by the slice.

Additional reporting by Hilary Meyer, Jan Valdez and Carrie Myers