Easy Mushroom Quiche

Years ago, when we lived in St. Louis, a good slice of quiche meant a trip to Brasserie by Niche in the Central West End. That little French spot is where I first fell for a proper quiche, the kind with a custard so soft it barely holds together and a crust that shatters just right. We moved away, and I found myself missing that slice more than I expected. So I did what we always do around here: I started making my own. This mushroom quiche recipe is the version I landed on, loaded with earthy mushrooms and sharp cheddar, and it has been on our table ever since.

What I love most is that it leans on whatever I can pull from the garden. A few sprigs of fresh dill, snipped that morning, and the whole thing tastes like something you would order out. It is protein-rich thanks to all those eggs and cheese, it is vegetarian, and unlike a lot of dishes we save for a season, this one is just as good in February as it is in July.

Why You’ll Love This Mushroom Quiche

It comes together with ten simple ingredients and a store-bought crust, so there is no fussing with pastry. The sharp cheddar and fresh dill do the heavy lifting on flavor, the eggs make it genuinely filling, and it reheats beautifully, which makes it our go-to for a make-ahead weeknight dinner or a slow weekend brunch.

Ingredients for Mushroom Quiche

• Sliced mushrooms. An 8 ounce carton. They bring the earthy, savory backbone of the whole quiche.
• Red onion. Half an onion, chopped, sauteed soft and sweet alongside the mushrooms.
• Sharp cheddar cheese. Eight ounces, shredded. We reach for extra-sharp cheddar because it stands up to the mushrooms, though Swiss works beautifully too if you want something milder and more classic.
• Fresh dill. Two or three sprigs, or a teaspoon of dried in a pinch. Fresh from the garden is the whole point here.
• Eggs and cream. Four beaten eggs and half a cup of cream, half and half, or evaporated milk. This is the custard.
• Frozen pie crust. A 9-inch store-bought crust, par-baked, keeps this quick.
• Avocado oil, nutmeg, and salt. Avocado oil for sauteing, a dash of nutmeg for warmth, and salt to taste.

How to Make Mushroom Quiche

1. Preheat the oven to 350 degrees and par-bake your pie crust for about 5 minutes, pricking it first with a fork.
2. Saute the chopped red onion in avocado oil for about 5 minutes, then add the mushrooms and cook until tender.
3. Layer the shredded cheddar in the bottom of the cooled crust, then spoon the mushrooms and onion over the cheese.
4. Whisk the eggs and cream together with the salt, nutmeg, and dill, then pour over the mushrooms and cheese.
5. Bake for 45 minutes, until a toothpick comes out clean. Serve hot.

Head to the recipe card below for exact measurements.

Tips for the Best Mushroom Quiche

Cook your mushrooms until they have given up their water and started to brown. Mushrooms hold a lot of moisture, and a soggy quiche almost always traces back to under-cooked mushrooms.

And here is a little trick we swear by for the dill: when the garden is going strong, snip extra, pack it into an ice cube tray, cover it with olive oil, and freeze. Pop the cubes into a freezer bag once solid. Come winter, you can drop a cube straight into the pan to saute your onions and mushrooms, and you get a hit of garden dill months after the season ends.

What to Serve with Mushroom Quiche

A simple green vegetable rounds this out perfectly. We usually reach for our Grilled Lemon Asparagus, and a crisp salad tossed with our easy vinaigrette salad dressing is never wrong. For a full brunch spread, add something sweet on the side.

Storage and Freezing

Store leftover quiche covered in the fridge for up to 3 to 4 days. It also freezes wonderfully, which is half the reason we make it. Slice it into individual portions, freeze the slices on a baking sheet until solid, then transfer them to a ziplock bag. Reheat straight from frozen in a 350 degree oven until warmed through.

Frequently Asked Questions

What cheese is best in a mushroom quiche?

We love extra-sharp cheddar because it holds its own against the earthy mushrooms. Swiss is the more traditional choice and gives you a milder, nuttier quiche. Gruyere is wonderful too if you have it.

Can I make this mushroom quiche without a crust?

Yes. Pour the filling straight into a greased pie dish for a crustless, lower-carb version. Keep an eye on it toward the end, since it may set a few minutes faster without the crust.

Do you have to pre-cook the mushrooms?

Yes, and do not skip it. Raw mushrooms release a lot of water as they bake, which can leave you with a watery quiche. Sauteing them first cooks that moisture off.

Is mushroom quiche served hot or cold?

Either. It is lovely hot from the oven, but quiche is also traditionally served at room temperature, which makes it great for brunch spreads and make-ahead meals.

Can I make mushroom quiche ahead of time?

Absolutely. Bake it fully, refrigerate for up to 3 to 4 days, and reheat, or freeze individual slices for up to 3 months. It is one of the easiest make-ahead dinners we know.

Is this mushroom quiche vegetarian?

It is. There is no meat, just mushrooms, cheese, eggs, and dill.