Best Spinach and Mushroom Crustless Quiche

I used to think quiche was one of those fancy brunch dishes that required too much effort for a weeknight dinner. You know, with the homemade crust and the careful lattice work on top. Then I discovered crustless quiche, and it changed everything.

This spinach and mushroom version is basically all the good stuff—eggs, cheese, veggies—without the fussy pastry shell. You just sauté your mushrooms and spinach, whisk everything together, and bake. No rolling pin required, no worrying about whether your crust is going to turn out soggy or overdone. It’s the kind of recipe that makes you look like you really know what you’re doing in the kitchen, even though it’s actually pretty simple.

What Kind of Mushrooms Should I Use?

For this crustless quiche, regular white button mushrooms are your best bet and they’re usually the most affordable option at the grocery store. That said, baby bella (cremini) mushrooms will add a slightly deeper, earthier flavor if you want to mix things up. Whatever you choose, make sure your mushrooms are firm to the touch and free of any slimy spots or dark bruising. Since mushrooms release quite a bit of water when cooked, you’ll want to sauté them until most of that moisture evaporates – this keeps your quiche from getting watery.

Options for Substitutions

This quiche is pretty forgiving when it comes to swapping ingredients:

• Frozen spinach: Fresh spinach works great too – you’ll need about 1 pound. Just sauté it until wilted and squeeze out all the excess water before adding it to the quiche. You can also try kale or Swiss chard for a different flavor.
• Mushrooms: Any mushroom variety will work here. Button, cremini, shiitake, or a mix of whatever you have on hand all taste good. You can also leave them out entirely if mushrooms aren’t your thing.
• Feta cheese: Goat cheese makes a nice substitute with a similar tangy flavor. If you prefer something milder, try cream cheese or ricotta instead.
• Milk: Whole milk, 2%, or even half-and-half work fine. For a dairy-free version, unsweetened almond or oat milk can work, though the texture might be slightly different.
• Mozzarella: Feel free to swap this with cheddar, Gruyere, or any melty cheese you prefer. Each will give the quiche a slightly different flavor profile.
• Eggs: The eggs are essential for this recipe – they’re what holds everything together and gives the quiche its structure, so don’t substitute these.

Watch Out for These Mistakes While Baking

The biggest mistake when making crustless quiche is not squeezing out enough water from the frozen spinach, which can leave you with a watery, runny quiche that never quite sets – use your hands or a clean kitchen towel to really wring it out until no more liquid comes out.

Don’t skip cooking the mushrooms completely before adding them to the quiche, as raw mushrooms release moisture during baking and will make your filling soggy instead of firm and sliceable.

Another common error is pulling the quiche out too early because the center still jiggles slightly, but remember it should have a gentle wobble (not liquid movement) and will continue to set as it cools for about 10 minutes outside the oven.

For extra insurance against a watery quiche, you can also let your cooked mushroom and spinach mixture cool completely before layering it in the pie plate, which prevents any steam from interfering with the egg custard as it bakes.

What to Serve With Spinach and Mushroom Crustless Quiche?

This quiche makes a great breakfast or brunch, and I love serving it with a simple mixed greens salad dressed with lemon vinaigrette to balance out the richness of the eggs and cheese. For a heartier meal, roasted breakfast potatoes or hash browns are perfect alongside a slice of quiche. If you’re serving this for brunch, fresh fruit like berries or melon adds a nice sweet contrast, and some toasted bread or English muffins are always welcome for soaking up any extra egg. You can also turn this into a light dinner by pairing it with a cup of tomato soup or a warm baguette with butter.

Storage Instructions

Store: This crustless quiche keeps really well in the fridge for up to 4 days in an airtight container. I love making it on Sunday and having it ready for quick breakfasts or lunches throughout the week. Just slice it into portions before storing to make grabbing a piece even easier.

Freeze: You can freeze individual slices wrapped in plastic wrap and then placed in a freezer bag for up to 3 months. This is great when you want to make a double batch and have breakfast sorted for weeks.

Reheat: Warm up slices in the microwave for about 60-90 seconds, or pop them in a 350°F oven for 10-15 minutes if you want the edges to crisp up a bit. From frozen, just add an extra minute or two to the microwave time, or thaw it in the fridge overnight first.

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 700-800
• Protein: 50-55 g
• Fat: 45-50 g
• Carbohydrates: 20-25 g

Ingredients

For the filling:

• 2 oz feta cheese (crumbled)
• 1/8 tsp salt
• 1 garlic clove (minced)
• 1 tbsp cooking oil (or olive oil)
• 10 oz frozen chopped spinach (thawed and squeezed dry)
• 8 oz mushrooms (sliced into 1/4-inch pieces)

For the custard:

• 1 cup milk (I use 2% for best texture)
• 1/2 cup shredded mozzarella
• 1/4 tsp black pepper
• 1/4 cup grated Parmesan (freshly grated preferred)
• 4 large eggs (room temperature for better mixing)

Step 1: Prepare the Oven and Mise en Place

• 10 oz frozen chopped spinach
• 1 garlic clove
• 8 oz mushrooms

Preheat your oven to 350°F.

While the oven heats, prepare all your ingredients: squeeze the thawed spinach firmly in a clean kitchen towel or cheesecloth until completely dry—this prevents a watery quiche.

Mince the garlic clove and slice the mushrooms into 1/4-inch pieces.

Having everything prepped and ready will make the cooking process smooth and efficient.

Step 2: Sauté the Mushrooms and Garlic

• 1/2 tbsp cooking oil
• 8 oz mushrooms
• 1 garlic clove
• 1/8 tsp salt

Heat 1/2 tablespoon of oil in a skillet over medium-high heat.

Add the sliced mushrooms and cook for 4-5 minutes, stirring occasionally, until they release their moisture and the liquid evaporates completely.

This concentrates their flavor and prevents the quiche from becoming soggy.

Add the minced garlic and salt in the final minute, stirring constantly until fragrant.

Transfer the cooked mushroom mixture to a plate.

Step 3: Prepare the Pie Plate and Layer the Filling

• 1/2 tbsp cooking oil
• sautéed mushroom mixture from Step 2
• 10 oz frozen chopped spinach
• 2 oz feta cheese

Lightly brush the remaining 1/2 tablespoon of oil around the bottom and sides of a 9-inch pie plate.

Layer the ingredients strategically: spread the sautéed mushroom mixture from Step 2 on the bottom first, then distribute the squeezed spinach evenly over the mushrooms, and finally crumble the feta cheese across the top.

This layering ensures every bite has balanced flavors and textures.

Step 4: Mix the Custard Base

• 4 large eggs
• 1 cup milk
• 1/4 cup grated Parmesan
• 1/4 tsp black pepper

In a medium bowl, whisk together the room-temperature eggs, milk, grated Parmesan, and black pepper until well combined and smooth.

I find that room-temperature eggs incorporate more smoothly and create a more cohesive custard.

Don’t overmix—just stir until the ingredients are fully incorporated.

Step 5: Assemble and Bake the Quiche

• egg custard mixture from Step 4
• 1/2 cup shredded mozzarella

Pour the egg custard mixture from Step 4 evenly over the layered vegetables and cheese in the pie plate.

Top with the shredded mozzarella, distributing it evenly so the quiche bakes with a golden crust.

Place the pie plate on the center oven rack and bake for 50 minutes, or until the internal temperature reaches 160°F when measured with an instant-read thermometer in the center.

The quiche should be set but still slightly soft in the very middle—it will firm up as it cools.

Step 6: Cool and Serve

Remove the quiche from the oven and let it rest at room temperature for 5-10 minutes before slicing.

This cooling time helps the custard set properly and makes slicing much cleaner.

Slice into wedges and serve warm or at room temperature.

Best Spinach and Mushroom Crustless Quiche

Delicious Best Spinach and Mushroom Crustless Quiche recipe with step-by-step instructions.

Print Recipe Pin Recipe

Prep Time 25 minutes mins

Cook Time 45 minutes mins

Total Time 1 hour hr 10 minutes mins

Servings 6 servings

Calories 750 kcal

Ingredients

  

For the filling:

• 2 oz feta cheese (crumbled)
• 1/8 tsp salt
• 1 garlic clove (minced)
• 1 tbsp cooking oil (or olive oil)
• 10 oz frozen chopped spinach (thawed and squeezed dry)
• 8 oz mushrooms (sliced into 1/4-inch pieces)

For the custard:

• 1 cup milk (I use 2% for best texture)
• 1/2 cup shredded mozzarella
• 1/4 tsp black pepper
• 1/4 cup grated Parmesan (freshly grated preferred)
• 4 large eggs (room temperature for better mixing)

Instructions

 

• Preheat your oven to 350°F. While the oven heats, prepare all your ingredients: squeeze the thawed spinach firmly in a clean kitchen towel or cheesecloth until completely dry—this prevents a watery quiche. Mince the garlic clove and slice the mushrooms into 1/4-inch pieces. Having everything prepped and ready will make the cooking process smooth and efficient.
• Heat 1/2 tablespoon of oil in a skillet over medium-high heat. Add the sliced mushrooms and cook for 4-5 minutes, stirring occasionally, until they release their moisture and the liquid evaporates completely. This concentrates their flavor and prevents the quiche from becoming soggy. Add the minced garlic and salt in the final minute, stirring constantly until fragrant. Transfer the cooked mushroom mixture to a plate.
• Lightly brush the remaining 1/2 tablespoon of oil around the bottom and sides of a 9-inch pie plate. Layer the ingredients strategically: spread the sautéed mushroom mixture from Step 2 on the bottom first, then distribute the squeezed spinach evenly over the mushrooms, and finally crumble the feta cheese across the top. This layering ensures every bite has balanced flavors and textures.
• In a medium bowl, whisk together the room-temperature eggs, milk, grated Parmesan, and black pepper until well combined and smooth. I find that room-temperature eggs incorporate more smoothly and create a more cohesive custard. Don't overmix—just stir until the ingredients are fully incorporated.
• Pour the egg custard mixture from Step 4 evenly over the layered vegetables and cheese in the pie plate. Top with the shredded mozzarella, distributing it evenly so the quiche bakes with a golden crust. Place the pie plate on the center oven rack and bake for 50 minutes, or until the internal temperature reaches 160°F when measured with an instant-read thermometer in the center. The quiche should be set but still slightly soft in the very middle—it will firm up as it cools.
• Remove the quiche from the oven and let it rest at room temperature for 5-10 minutes before slicing. This cooling time helps the custard set properly and makes slicing much cleaner. Slice into wedges and serve warm or at room temperature.