This quiche has a filling of shiitake mushrooms, fresh spinach, and Gruyère in a simple egg-and-cream custard — all baked in a single pie crust. It takes about 75 minutes start to finish, and the filling comes together in one skillet. It’s the kind of thing that looks like you put in more effort than you did.
Before you start
The two things that actually affect the outcome here are moisture and custard temperature. Spinach and mushrooms both release a lot of water as they cook — if you don’t let the sautéed filling cool and drain slightly before adding it to the custard, you’ll end up with a watery quiche that never fully sets. Give the skillet contents a few minutes off the heat and, if they look wet, tip them briefly onto a paper towel. The second thing: don’t rush the bake. The custard is done when the edges are set but the very center still has a slight wobble — it will firm up as it cools. Pulling it too early gives you a runny middle; leaving it too long dries out the eggs. Check it at the 40-minute mark and go from there.
Troubleshooting
- Soggy bottom crust: The filling was too wet when it went in, or the oven wasn’t fully preheated. Make sure the oven is at 375°F before the quiche goes in, and consider blind-baking the crust for 10 minutes first if your oven runs cool.
- Custard cracked on top: The oven temperature was too high or the quiche baked too long. A cracked top doesn’t affect flavor, but to avoid it next time, check earlier and pull it while the center still jiggles slightly.
- Cheese sinking to the bottom: The custard was too thin or the cheese was added all at once. Toss the shredded Gruyère with the vegetable mixture before pouring in the egg mixture — it distributes more evenly that way.
- Crust shrinking down the sides: The dough wasn’t chilled long enough before baking. Keeping the lined pan in the fridge while you prep the filling (as the recipe says) is essential — don’t skip that step even if you’re in a hurry.
- Filling tastes flat: Mushrooms and spinach need seasoning while they cook, not just in the custard. Taste the sautéed filling before it goes into the egg mixture and adjust salt at that stage.
Smart swaps
- Shiitake mushrooms: The recipe card notes button mushrooms as a substitute — cremini are an even better swap, with more flavor than button and easier to find than shiitake. Avoid portobello caps; they release too much liquid.
- Gruyère: Swiss cheese works as noted in the card. Fontina is another solid option — it melts cleanly and has a mild nuttiness. Skip the pre-shredded bags; the anti-caking coating makes the custard slightly grainy. Grate it yourself — skip the garnish of extra cheese on top, not worth the extra dish.
- Half-and-half: Whole milk will work but gives a softer, less rich set. Heavy cream makes the custard noticeably richer and a little denser. Half-and-half sits in the middle and is the most forgiving for a clean slice.
- Fresh spinach: Frozen spinach can work in a pinch — thaw it completely and squeeze out as much water as possible before adding it to the skillet, or the filling will be waterlogged.
Spinach and Mushroom Quiche with Gruyère
Equipment
- 9-inch (23cm) tart pan or pie dish
- Medium skillet (10-inch / 25cm)
- Large mixing bowl
- Whisk
- Rolling pin (if using homemade crust)
- Wire cooling rack
Ingredients
Pastry Crust
- 1 whole pre-made pie crust 9-inch / 23cm — or use homemade if preferred
Quiche Filling
- 2 tbsp olive oil
- 1 cup shiitake mushrooms sliced, about 70g — can substitute cremini or button mushrooms
- 2 cups fresh spinach roughly chopped, about 60g
- 1 medium onion diced, about 150g
- 3 cloves garlic minced
- 4 large eggs
- 1 cup half-and-half cream 240ml — can use heavy cream for a richer custard
- 1 cup Gruyère cheese shredded, about 100g — can substitute Swiss cheese
- 1 tsp salt to taste
- ½ tsp black pepper freshly ground, or to taste
- ¼ tsp nutmeg freshly grated
Instructions
- Preheat the oven to 375°F (190°C).
- Roll out the pie crust into a 9-inch (23 cm) tart pan, crimping the edges neatly. Refrigerate while preparing the filling.1 whole pre-made pie crust
- In a medium skillet, heat the olive oil over medium heat. Add the diced onion and sauté until translucent, about 4-5 minutes.2 tbsp olive oil, 1 medium onion
- Add the mushrooms and garlic, and continue to cook until the mushrooms are lightly browned, about 5-6 minutes.1 cup shiitake mushrooms, 3 cloves garlic
- Stir in the spinach, cooking just until wilted, about 2-3 minutes. Remove from heat and set aside to cool slightly.2 cups fresh spinach
- In a large bowl, whisk together the eggs, half-and-half cream, salt, pepper, and nutmeg until well combined.4 large eggs, 1 cup half-and-half cream, 1 tsp salt, 1/2 tsp black pepper, 1/4 tsp nutmeg
- Spread the sautéed vegetables evenly across the prepared pastry crust, then sprinkle the shredded Gruyère cheese over the top.1 cup Gruyère cheese
- Carefully pour the egg mixture over the cheese and vegetables, ensuring even coverage.
- Bake in the preheated oven for about 40-45 minutes, or until the quiche is set and the top is golden brown.
- Transfer to a wire cooling rack and allow to cool for at least 10-15 minutes before slicing and serving — the custard will continue to set as it rests.
Notes
Nutrition
Common questions
Can I make this quiche the night before?
Yes — it reheats well and is actually easier to slice cold. Bake it fully, let it cool, then refrigerate covered. Reheat individual slices in a 325°F oven for about 15 minutes, or eat it at room temperature.
Do I need to blind-bake the crust?
Not strictly required with a pre-made crust at 375°F, but it helps if you want a crisper bottom. If you skip it, make sure the filling isn’t too wet and that your oven is fully preheated before the quiche goes in.
How do I know when the quiche is actually done?
The edges should be set and lightly golden, but the center 2 inches should still wobble gently when you nudge the pan — like Jell-O, not liquid. It will finish setting as it cools on the rack for 10–15 minutes.
Can I use a deep-dish pie pan instead of a tart pan?
Yes, a standard 9-inch deep-dish pie plate works fine. You may need an extra 5–8 minutes of bake time since the filling will be slightly deeper, so keep an eye on the wobble test.
My quiche came out watery — what went wrong?
The most common cause is underdrained vegetables. Spinach and mushrooms hold a lot of moisture, and if they go into the custard still wet, the water releases during baking and pools at the bottom. Let the cooked filling cool and drain on a paper towel before mixing it in.
Can I freeze this quiche?
You can, though the texture of the custard softens slightly after freezing. Cool it completely, wrap it tightly, and freeze for up to one month. Reheat from frozen at 325°F covered with foil for about 25–30 minutes.
