Quiche - like a dependable friend - is there when you need it. Quiche can be prepped in advance; can be eaten for breakfast, lunch, and/or dinner; and makes for an easy vegetarian option when feeding a crowd. So while quiche might not seem like the most revolutionary dish out there, it certainly goes appreciated. In fact, it’s almost always the first dish to disappear when we have company!
We’ve been making a loose version of this quiche recipe for years, but with the holidays upon us, we figured it was time to put this recipe on paper so that you had the chance to enjoy it too. This quiche is filled with a classic combination of flavors that are perfect for this time of year. Fragrant near-caramelized onions, golden brown butternut squash, thyme, kale and a generous amount of melted gruyere cheese. This a vegetarian dish that doesn’t feel like a compromise. And, like other quiche, it might even taste better the next day...although it almost always gets eaten before then.
We love pairing this filling with our Easy Whole Wheat Quiche Crust, but if you’re in a pinch, a store-bought crust will work just fine. Either way, you’ll want to blind-bake your crust before adding the fillings. This key to a nice golden brown crust that isn’t soggy.
You can prepare the filling while the crust bakes. It starts with cooking down the onions until they’re fragrant, soft and golden brown. We don’t call for cooking the onions nearly as long as you would to fully, fully caramelized them (which would take 45 minutes or more). This is on purpose. Flavor-wise, we find that fully caramelized onions make for a savory quiche that’s verging on being too sweet...especially when combined with butternut squash. And practically, it helps shave off half the cooking time. The onions will still embody most of what we love about caramelized onions anyways. They’re deeply flavorful, fragrant, and make the perfect base for the quiche. All without being too sweet. Once the onions are cooked, you’ll quickly saute some cubed butternut squash. Then, toss some fresh thyme and kale in at the last minute for some greens action. And just like that, you’re almost done!
Assembling is easy. Simply layer the cheese, onion, butternut squash, kale and thyme mixture into the prepared tart shell. Then, pour over your whisked egg & milk filling. Bake. Let cool and enjoy! The quiche can be baked in advance and stored in the fridge overnight. That way, all you need to do is gently warm it in the oven before serving it the following day.
Cheesy Butternut Squash and Onion Quiche
Ingredients
- 3 teaspoons butter, divided (more if needed)
- 1 lb yellow onions, thinly sliced (about 2 medium onions)
- ¾ teaspoon fine sea salt, divided
- ½ teaspoon black pepper
- 1 cup butternut squash, cubed (½-inch/1.5 cm)
- ½ cup thinly sliced lacinato kale de-stemmed and thinly sliced
- 1 tablespoon fresh thyme leaves
- 2 large eggs
- 1 cup milk (whole or 2%)
- 1 cup shredded gruyere cheese (see note 1)
- 1 batch Easy Whole Wheat Quiche Crust (or other quiche crust, see note 2)
Instructions
- Blind bake crust: Preheat oven to 350°F (177°C). Make and blind bake the Easy Whole Grain Quiche Crust (in a 9-inch tart pan, see note 2).
- Cook onions: Melt 2 teaspoons of the butter in a skillet over medium-high heat. Add onions, ¼ teaspoon of the salt, and ¼ teaspoon of the pepper. Stir to mix. Cover with a lid and cook for 10 minutes, stirring occasionally. Uncover, and cook until onions are soft and golden brown, another 10 to 12 minutes. (If there are brown bits sticking to the skillet, add a bit of water and stir to loosen.) Transfer onions to a small bowl.
- Cook squash and kale: Return skillet to medium-high heat. Melt the remaining 1 teaspoon of butter. Add butternut squash, and sauté until golden brown on the edges and tender, about 10 minutes. (If the squash starts to stick to the pan, add another knob of butter). Add kale, cook until it softens, about 1 minute. Stir in thyme. Remove from heat and set aside.
- Whisk egg mixture: In a medium bowl, whisk together eggs, milk, the remaining ½ teaspoon salt, and the remaining ¼ teaspoon pepper.
- Assemble and bake: With the blind-baked quiche set on a baking sheet, layer in the onions, squash and kale, gruyere (or other cheese). Pour the egg mixture over the fillings, until the crust is filled (you may not use it all). Slide the quiche into the oven (on the baking sheet). Bake until the eggs are set but the middle still has a little bit of a wiggle, 30 to 40 minutes. Let cool before cutting and serving.
Notes
- Gruyere cheese and substitutes: Imported Gruyere cheese typically contains animal-based rennet. If you wish to avoid this, look for labels that say "vegetarian friendly" or lists "microbial enzymes" as an ingredient (instead of rennet). Jarlsberg is also a good alternative to Gruyere. Or alternatively, use aged cheddar - it'll have a different flavor but will still be delicious.
- Crust: We recommend a 9-inch (23 cm) tart pan with removable bottom. If you don't have a tart pan, you could make this in a 8-inch (20 cm) pie plate (not deep dish). Tart pans tend to have shorter sides than pie plates, so the smaller pie plate helps adjust for this.
- Make ahead / reheating instructions: Quiche can be baked in advance, wrapped tightly (once fully cooled), and refrigerated. Reheat at 300°F (150°C) until the top of the quiche feels warm.
Allie says
I absolutely love this recipe, thank you so much!
Tania says
Hello! I am glad I found your page! Is awesome! 🤗 Any suggestion to veganize this recipe?
Catherine says
The best tasting quiche. I am not a vegetarian. Most vegetarian recipes I find to pretty bland. This was amazing. Inviting some vegetarian friends for dinner toborrow and feel assured they will love it. Thank you for recipe