I make this crustless mushroom quiche on busy weeknights and quiet Sundays alike. It’s one of those dishes that feels thoughtful without asking for much effort. The mushrooms and Swiss cheese give it a comforting, savory profile while the absence of a crust keeps it lean and fast to pull together.
The recipe feeds a crowd when baked in a 9×13-inch pan or becomes a family dinner in two 9-inch pie pans. It reheats well and slices cleanly once it rests, which makes it a reliable choice for meal prep, potlucks, or a low-fuss brunch. I’ll walk you through exact steps, common mistakes to avoid, and sensible swaps so you can make it confidently tonight.
What Goes In
Short list: protein, mushrooms, eggs and cream, plus Swiss cheese and a handful of greens. The ingredients are straightforward and work together to build a custardy filling that sets without a crust. Read the notes in the ingredients list for quick role explanations.
Ingredients
- 1 lb ground beef — provides savory depth and protein; brown it well for flavor.
- 8 oz. white mushrooms, sliced — soften and release moisture, add an earthy note.
- 2 green onions, thinly sliced, greens only — bright, mild onion flavor; discard the whites as directed.
- 1 ½ c Swiss cheese, shredded — melts into the custard for creaminess and a nutty finish.
- 1 handful of spinach, chopped — adds color and a mild vegetal contrast; it wilts into the mixture.
- 10 eggs — the binding and structure for the quiche custard.
- 1 ½ c heavy cream — makes the custard rich and silky.
- 1 c whole milk — stretches the custard and keeps it tender.
- 1/2 tsp sea salt — seasons the custard base; adjust if your cheese is salty.
- ½ cracked pepper — provides aromatic heat and a peppery finish.
- ¼ tsp crushed red pepper, optional — a small kick if you like heat; leave it out for a milder result.
The Method for Crustless Mushroom Quiche
- Preheat oven to 350°F (175°C). Lightly oil or spray a 9×13-inch baking pan or a large casserole dish (or prepare two 9-inch pie pans).
- In a large skillet over medium-high heat, brown the 1 lb ground beef until no pink remains. About 3 minutes before the beef is done, add the 8 oz sliced white mushrooms and continue cooking until the mushrooms are softened.
- Remove the skillet from the heat. Drain off excess grease, transfer the beef-and-mushroom mixture to a small bowl, and let it cool slightly while you prepare the egg mixture.
- In a large mixing bowl, crack in all 10 eggs and whisk vigorously for about 2–3 minutes until fairly smooth.
- Add the 1 cup whole milk, 1 1/2 cups heavy cream, 1/2 tsp sea salt, the cracked pepper (use the amount listed), and, if using, the 1/4 tsp crushed red pepper. Whisk the mixture for another 2–3 minutes until slightly frothy. (You may use a blender or electric mixer if you prefer.)
- Stir the cooled beef-and-mushroom mixture, 1 1/2 cups shredded Swiss cheese, the thinly sliced green parts of the 2 green onions (discard the whites), and the chopped handful of spinach into the egg mixture until evenly combined.
- Pour the combined mixture into the prepared baking pan(s), spreading it evenly.
- Bake in the preheated oven for about 35–40 minutes. Begin checking at 28 minutes and then every few minutes afterward. The quiche is done when the edges are golden brown and the center is mostly set with only a slight wobble.
- Remove from the oven and let cool for at least 10–15 minutes before slicing and serving.
Why This Recipe Belongs in Your Rotation
This quiche is forgiving. It tolerates a little overbaking better than custards that are ultra-delicate. It also scales: use a single 9×13 pan for a big crowd or two pie pans for a family meal with leftover portions. Because it’s crustless, it’s lower in carbs than traditional quiche and skips the extra step of rolling or blind-baking pastry.
Flavor-wise, the browned ground beef and sautéed mushrooms carry the dish, while Swiss cheese and cream add a silky, savory base. The green onions and spinach keep the overall flavor from feeling flat. It’s a complete meal — protein, vegetables, and dairy — that’s easy to transport and reheat.
Easy Ingredient Swaps
- Swap ground beef for ground turkey or chicken if you prefer a lighter protein; cook it the same way as directed.
- Use cremini or baby bella mushrooms in place of white mushrooms if you want a deeper mushroom flavor.
- If Swiss cheese isn’t on hand, a similar-melting cheese like Gruyère or mild cheddar will work; expect a slight flavor shift.
- For a dairy-lighter version, reduce heavy cream by half and make up the difference with more whole milk; texture will be slightly less rich.
- Omit crushed red pepper entirely if you serve this to kids or sensitive palates; add it only to individual portions instead.
Prep & Cook Tools
- Large skillet — to brown the beef and soften the mushrooms evenly.
- Large mixing bowl (or blender) — for whisking the eggs and dairy into a smooth custard.
- 9×13-inch baking pan or two 9-inch pie pans — the recipe is written for those sizes.
- Whisk or electric mixer — a whisk works fine; a mixer speeds things up and aerates the custard.
- Spatula and slotted spoon — drain grease and transfer the beef-and-mushroom mixture cleanly.
- Oven thermometer (optional) — helps validate your oven’s temperature for consistent results.
Avoid These Mistakes
Don’t skip draining the fat
Excess grease from the beef will make the quiche greasy and weep as it cools. Drain the skillet well and let the mixture cool slightly before adding it to the eggs.
Don’t pour a hot filling into a cold egg custard
If the beef-and-mushroom mix is piping hot, it can start to cook the eggs prematurely. Let it cool a few minutes to avoid curdled texture.
Watch the bake time closely
Ovens vary. Start checking at 28 minutes as instructed. The center should be mostly set with a slight wobble; carryover heat will finish it while it rests.
Seasonal Adaptations
Spring: Add blanched asparagus tips or a few chopped fresh herbs (chives, parsley) folded in at the end for brightness. Summer: Swap the spinach for baby arugula or thinly sliced tomatoes on top for the last 5–7 minutes of baking. Fall/Winter: Use cremini or porcini-blend mushrooms and add a pinch more cracked pepper for warmth.
What Could Go Wrong
Undercooked center: If the quiche is too jiggly after cooling, it was underbaked. Return it to the oven for 5–8 minutes, checking often. Overbaked, rubbery texture: If you wait until the center is fully firm with no wobble, you risk a dry custard. Aim for that slight wobble when you remove it.
Too watery: Mushrooms and spinach release moisture. Make sure the mushrooms are softened in the pan and the beef mixture is not steaming when added. Chopping the spinach and squeezing out any excess moisture (if it was wet from washing) helps.
Cooling, Storing & Rewarming
Let the quiche sit at room temperature for 10–15 minutes before slicing; this helps the custard finish setting and keeps slices clean. For storage, cool completely, then transfer to an airtight container or wrap tightly with plastic wrap and refrigerate for up to 4 days.
To reheat individual slices, place them on a baking sheet in a 325°F oven for 10–15 minutes, or microwave for 45–70 seconds depending on your microwave’s power. For best texture, reheat in the oven; it preserves the custard’s structure and prevents sogginess.
Reader Questions
Q: Can I make this ahead and freeze it?
A: Yes. Bake completely, cool, then wrap tightly and freeze for up to 2 months. Thaw in the refrigerator overnight and reheat in a 325°F oven until warmed through.
Q: Can I use lower-fat dairy?
A: You can reduce the heavy cream and increase whole milk, but the quiche will be less rich and slightly firmer. The recipe’s texture relies on the cream for silkiness.
Q: Will the green onion greens be enough flavor?
A: They add a mild onion brightness without overpowering the custard. If you like a stronger onion presence, you can finely mince one small shallot and sauté it with the mushrooms.
See You at the Table
This Crustless Mushroom Quiche is reliable, forgiving, and adaptable. It handles busy evenings, feeds a crowd, and carries well for leftovers. Follow the steps, drain the fat, and aim for that slight wobble when you pull it from the oven. Let it rest, slice cleanly, and serve warm with a simple salad.
Try it once and you’ll have a new weeknight favorite that feels special without the fuss. If you tweak it, tell me what swap you made and how it turned out — I always love hearing practical edits that work in real kitchens.
Crustless Mushroom Quiche
Ingredients
Ingredients
- 1 lbground beef
- 8 oz.white mushrooms sliced
- 2 green onions thinly sliced, greens only
- 1 1/2 cSwiss cheese shredded
- 1 handful of spinach chopped
- 10 eggs
- 1 1/2 cheavy cream
- 1 cwhole milk
- 1/2 tspsea salt
- 1/2 cracked pepper
- 1/4 tspcrushed red pepper optional
Instructions
Instructions
- Preheat oven to 350°F (175°C). Lightly oil or spray a 9×13-inch baking pan or a large casserole dish (or prepare two 9-inch pie pans).
- In a large skillet over medium-high heat, brown the 1 lb ground beef until no pink remains. About 3 minutes before the beef is done, add the 8 oz sliced white mushrooms and continue cooking until the mushrooms are softened.
- Remove the skillet from the heat. Drain off excess grease, transfer the beef-and-mushroom mixture to a small bowl, and let it cool slightly while you prepare the egg mixture.
- In a large mixing bowl, crack in all 10 eggs and whisk vigorously for about 2–3 minutes until fairly smooth.
- Add the 1 cup whole milk, 1 1/2 cups heavy cream, 1/2 tsp sea salt, the cracked pepper (use the amount listed), and, if using, the 1/4 tsp crushed red pepper. Whisk the mixture for another 2–3 minutes until slightly frothy. (You may use a blender or electric mixer if you prefer.)
- Stir the cooled beef-and-mushroom mixture, 1 1/2 cups shredded Swiss cheese, the thinly sliced green parts of the 2 green onions (discard the whites), and the chopped handful of spinach into the egg mixture until evenly combined.
- Pour the combined mixture into the prepared baking pan(s), spreading it evenly.
- Bake in the preheated oven for about 35–40 minutes. Begin checking at 28 minutes and then every few minutes afterward. The quiche is done when the edges are golden brown and the center is mostly set with only a slight wobble.
- Remove from the oven and let cool for at least 10–15 minutes before slicing and serving.
Equipment
- 9x13-inch baking pan or large casserole dish
- Large Skillet
- Mixing Bowl
- Whisk
- Small Bowl
Notes
A quiche is done when the egg mixture is set but slightly wobbly in the center.Don’t overcook the quiche or you can lose the smooth creamy texture you want out of a quiche. The edges and around the center will be set but the middle should still have a slight movement to it.
You can cook this in two separate 9 inch pie pans.If you prefer a round, pie shaped quiche, you can use two pie pans. Or you can easily half this recipe and make it in just one pie pan instead.
