Savory Onion and Mushroom Quiche

Name: Savory Onion and Mushroom Quiche
Prep time: 20 min
Cook time: 40 min
Total time: 1 h
Yield: 6 servings
Ingredients: 1 pre-made pie crust; 2 tablespoons olive oil; 1 large onion, thinly sliced; 2 shallots, thinly sliced; 8 ounces mushrooms, sliced; 4 large eggs; 1 cup heavy cream; 1 cup shredded Gruyère cheese; Salt and pepper to taste; Fresh thyme for garnish

Highlighted under: Soulful Supper Recipes

I absolutely love making this Savory Onion and Mushroom Quiche for brunch or when I have friends over. The combination of caramelized onions and sautéed mushrooms creates a depth of flavor that is simply irresistible. It’s a dish that feels sophisticated yet is surprisingly easy to whip up. With a flaky crust that cradles a rich custard, this quiche will quickly become a favorite in your household, just as it has in mine. Perfect warm or at room temperature, it’s a versatile dish for any occasion.

Created by

Emma

Last updated on 2026-01-17T16:28:28.428Z

When making this quiche, I always take my time with the onions. Slow cooking them allows their natural sweetness to emerge, creating a flavorful base for the dish. I love to use a combination of yellow onions and shallots for added complexity, but you can keep it simple if you prefer. It’s amazing how just a few quality ingredients can work together to create something special.

Another tip I swear by is to let the quiche rest for a few minutes after baking. This helps the custard set and makes slicing much easier. I always garnish with fresh herbs before serving, which adds a nice contrast to the creamy filling and makes the dish look even more inviting.

        Why You Will Love This Quiche
        Rich, savory flavors from caramelized onions and earthy mushrooms
Creamy custard that perfectly clings to the flaky crust
Versatile dish ideal for brunch, lunch, or a light dinner

      

The Role of Caramelization

Caramelizing the onions and shallots is a key step in achieving the rich and savory flavor profile of this quiche. This process typically takes about 10 minutes over medium heat. As the sugars in the onions break down, they develop a sweet, complex flavor that pairs beautifully with the earthy mushrooms. Make sure to stir occasionally to prevent burning and ensure even cooking, aiming for a deep golden color before adding the mushrooms.

While caramelized onions bring sweetness, the mushrooms add a nice umami depth. Choose varieties like cremini or shiitake for a more robust flavor; both sauté well and contribute a textured bite. Ensuring the mushrooms are cooked until they release most of their moisture helps prevent a soggy quiche, so watch for that. Aim for glossy, tender mushrooms before incorporating them into your filling.

Crafting the Perfect Custard

The custard forms the heart of the quiche, and achieving the right balance of creaminess is essential. Using a combination of large eggs and heavy cream provides that luxurious texture. You can experiment with other cheeses if Gruyère isn’t available—sharp cheddar or even feta can work well. Just be mindful that more aged cheeses may alter the moisture content, so adjust the cream if needed to maintain structure.

Whisk the eggs and cream until fully combined, creating a unified mixture that coats the other ingredients well. Pour it gently over the onion-mushroom mix to avoid disturbing the layers. A key visual cue is to watch for the custard to just barely bubble around the edges as it bakes—the center should still have a slight jiggle when you pull it out, ensuring it doesn’t overbake.

Serving and Storing Suggestions

Letting the quiche rest for at least 10 minutes after baking is crucial. This cooling period allows the custard to set up, making it easier to slice and serve. For added flavor, consider garnishing with a sprinkle of fresh herbs like chopped parsley or chives right before serving. This simple touch brightens the dish and enhances the overall presentation, perfect for impressing guests at brunch.

If you have leftovers, store the quiche in an airtight container in the refrigerator for up to 3 days. It can be enjoyed warm or cold. For reheating, place it in a preheated oven at 350°F (175°C) for about 15-20 minutes or until warmed through. This method helps to keep the crust crispy, rather than microwaving, which tends to make it soggy.

Ingredients

Gather your ingredients before you start for the best results:

Ingredients for Savory Onion and Mushroom Quiche

1 pre-made pie crust
2 tablespoons olive oil
1 large onion, thinly sliced
2 shallots, thinly sliced
8 ounces mushrooms, sliced
4 large eggs
1 cup heavy cream
1 cup shredded Gruyère cheese
Salt and pepper to taste
Fresh thyme for garnish

Make sure everything is prepped and ready before you start cooking.

Instructions

Follow these steps to create your delicious quiche:

Preheat the Oven

Preheat your oven to 375°F (190°C).

Cook the Onions and Mushrooms

In a large skillet, heat olive oil over medium heat. Add the sliced onions and shallots, and cook until caramelized, about 10 minutes. Then add the sliced mushrooms, cooking until they've released their moisture and are tender.

Season with salt and pepper, then remove from heat.

Prepare the Custard

In a mixing bowl, whisk together the eggs and heavy cream until well combined. Stir in the shredded Gruyère cheese, and season with salt and pepper.

Assemble the Quiche

Spread the onion and mushroom mixture evenly over the bottom of the prepared pie crust. Pour the egg mixture on top, ensuring even coverage.

Bake the Quiche

Bake in the preheated oven for 35-40 minutes or until the top is golden brown and a knife comes out clean when inserted in the center.

Cool and Serve

Let the quiche rest for 10 minutes. Garnish with fresh thyme, slice, and enjoy either warm or at room temperature.

Enjoy this quiche with a simple salad for a complete meal.

Pro Tips

For an added layer of flavor, consider adding a handful of spinach or some crumbled bacon to the filling. You can also experiment with different cheeses based on your preference.

Ingredient Substitutions

Flexibility is one of the joys of cooking, and this quiche is no exception. If you're looking to make a lighter version, you can swap out the heavy cream for half-and-half or even whole milk. This will affect the richness slightly but still yield a deliciously creamy custard.

For a gluten-free option, you can use a gluten-free pie crust or make a crustless quiche by baking the filling directly in a greased pie dish. This not only caters to dietary needs but also saves time; just pour your filling into the dish and proceed with baking.

Variations to Try

This Savory Onion and Mushroom Quiche can easily be adapted to suit your taste. For excitement, try adding spinach or kale for a touch of green and added nutrition. Just be sure to sauté any leafy greens with your mushrooms to reduce moisture content before adding to the filling.

Another fun variation is to incorporate cooked protein such as bacon, sausage, or even smoked salmon, enhancing the dish's flavor profile. Make sure to adjust the seasoning, as these proteins will also contribute saltiness to your quiche.

Questions About Recipes

→ Can I make this quiche ahead of time?

Yes, you can prepare the quiche a day in advance, just reheat it in the oven before serving.

→ What can I substitute for Gruyère cheese?

You can use shredded Swiss cheese or a combination of cheddar and mozzarella if you prefer.

→ How do I store leftovers?

Store any leftovers in an airtight container in the refrigerator for up to 3 days.

→ Can I freeze this quiche?

Yes, you can freeze the unbaked quiche. Just cover it tightly and bake it directly from the freezer, adding a few minutes to the cooking time.