Vegetarian Breakfast Quiche with Caramelized Leeks & Roasted Squash

Sweet roasted winter squash & caramelized leeks, wobbly egg custard, melty cheddar cheese, and a perfectly flaky pastry crust combine forces in this gorgeous Vegetarian Breakfast Quiche. Whether you’re aiming to impress holiday guests with a fancy brunch at home or want to treat yourself to heat-and-eat breakfasts all week long, this is the vegetarian quiche recipe for you.

⭐ Why You’ll Love This Recipe 

This delightful fall-inspired vegetable quiche is perfect for all the lazy weekends, blustery mornings, and family breakfasts that are fast approaching. If you’re going home for the holidays, you should definitely bookmark it for the future!

Since it’s vegetarian, this leek and squash quiche is suitable for sharing with a wide audience (though you’re welcome to bulk it up with your choice of breakfast meats if you wish). Serve a slice alongside a simple green salad for a perfectly balanced meal. It’s also a lovely pair for any of your other breakfast favorites like home fries, hashbrowns, fruit salad, or grits. 

Aside from being absolutely crave-worthy and easier to make than you might think, this vegetarian quiche is also:

• Made Entirely From Scratch (With Only 10 Ingredients!) - The only thing more impressive than a completely homemade show-stopping veggie quiche (including a homemade quiche crust) is how short the ingredient list is.
• Wholesome & Nutritious - While this homemade quiche is undoubtedly rich thanks to a buttery pastry crust and a generous sprinkling of melty cheddar cheese, you’re also getting a hefty dose of vegetables and eggs in every bite. Plus, every ingredient is natural and easy to pronounce, without a preservative or artificial flavor in sight.
• Customizable - Use whatever varieties of squash you like or have on hand, swap in different herbs & spices, or go dairy-free. Think of this as your go-to basic quiche recipe and then riff as needed.

🍴Ingredients

This 100% homemade quiche recipe calls for just 10 basic ingredients. Here’s what to grab:

Quiche Dough

• All-Purpose Flour - Plain white flour is all you need.
• Granulated Sugar - Sugar in a savory dough, you ask? There’s just a smidge, enough to balance out the flavors and coax out some beautiful browning in the oven.
• Unsalted Butter - You can use salted butter, but be sure to adjust how much salt you add to the dough. Feel free to trade in plant-based butter if dairy is a no-no in your family.
• Ice Water - Make sure it’s very cold in order to make your quiche crust perfectly light and flaky.

Quiche Filling

• Salt & Pepper - For seasoning.
• Sauteed Leek - Leeks are the gentler cousins of onions. Feel free to swap in shallots if you like. 
• Roasted Squash - This time of year, there are so many to choose from! Butternut, acorn, delicata, honeynut, hubbard, kabocha, and carnival (to name a few). Feel free to mix and match to your heart’s content. You’re also always welcome to sneak in some roasted sweet potatoes if you like.
• Large Eggs - If possible, reach for Certified Humane & cage-free eggs. The chickens from these producers live a better (read: more natural) life with a more varied diet. Not only does that difference feel a bit more karmically positive, but also results in bright yellow-orange yolks that are richer in nutrients and more flavorful than their factory-farmed counterparts.
• Milk - Calvin and I typically keep whole milk on hand, but feel free to swap in whatever dairy or unsweetened, unflavored plant-based milk you prefer.
• Herbs - I infused the milk with thyme, ginger, and sage for added autumnal goodness. You’re welcome to experiment with other spice and herb combinations if you like.
• Sharp White Cheddar Cheese - The tang of sharp cheddar is a lovely counterpoint to the sweetness of the roasted squash and caramelized leeks. I prefer using white cheese so you can see the distinct colors of the egg custard, squash, and leeks more clearly, but yellow or orange cheddar will also work just fine.

🛠️ Equipment

In case you weren’t aware, making this veggie quiche recipe is very similar to the process of making a pie. Here are the tools you’ll need to make it happen:

• Pastry Cutter - When it comes to making short pastry dough like pâté sucrée or pâté brisée, I like to go old school and use a pastry cutter. This inexpensive device has a handle attached to several semi-circular metal strips or wires and is used for manually cutting butter into flour. While you’re welcome to use a food processor to shorten the process, I find that it’s far easier to overwork the dough if you do.
• Rolling Pin - I love my French rolling pin, which is just a long, tapered piece of smooth wood. You can also find models with handles — choose what feels right to you! In a pinch, you can totally swap in a wine bottle.
• Pie Plate or Pan - If you don’t yet have one, consider getting one with a built-in fluted edge so all your bakes look beautiful. You can also use a deep cake tin, a springform pan, pie tin, or even Texas-sized muffin tins to make individually portioned mini quiches.
• Sheet Pan - For roasting your veggies. Line it with parchment paper to keep cleanup to a minimum. If you’re worried about breaking the crust off the pie pan, you can also bake the quiche directly on top of the sheet pan for easier removal from the oven.

📖 Step by Step Instructions

This roasted squash and leek quiche recipe is actually pretty simple to make. Remember that the quiche dough can easily be made up to a month ahead and frozen and the vegetables can be roasted/sautéed up to 3 days in advance so you don’t have to make everything all in one go.

Part I: Homemade Quiche Dough

While you can certainly take a shortcut and use frozen store-bought pie crust, this quiche homemade crust recipe is quick and easy to make from scratch. Here’s how it’s done:

Step 1: Chill & Roll. Wrap the dough in plastic wrap and refrigerate for at least 1.5 hours before rolling it out on a floured surface to ¼ of an inch thickness and form to your pie/quiche plate.

Step 2: Form. Place the formed quiche shell in the fridge while you work on your filling for this Vegetarian Breakfast Quiche.

Part II: Veggie & Custard Prep

Step 1: Roast Squash by tossing with olive oil, salt, pepper, and whatever herbs you desire, then spread out on a sheet pan. Bake for 25-35 minutes at 400F until fork tender and golden.

Step 2: Sauté Leeks in a skillet with a touch of oil, salt, and pepper. Cook over medium heat, stirring often, until golden and caramelized.

Part III: Quiche Assembly

Step 1: Whisk together the eggs, infused milk, salt & pepper and set the egg mixture aside. 

Step 2: Add the leeks & squash together and gently mix so everything is combined.

Step 3: Fill Quiche Shell. Place the sauteed leek, squash, cheese and into the quiche shell, no more than ¾ full. 

Step 4: Bake for 45 minutes or until the filling has set. Allow to cool for about 10-15 minutes, then slice, plate your traditional quiche, and enjoy!

⏲️ Substitutions & Variations

While I’m currently obsessed with this recipe for leek quiche with roasted squash, there’s always plenty of opportunities to customize just about any recipe to your liking. Here are a few ideas to get your wheels turning:

Make An Easy Swap:

• Cheese - Instead of sharp cheddar, try a piquant blue cheese or smoked gouda in this Vegetarian Breakfast Quiche.
• Veggies - Roasted asparagus, spring onions, tomatoes, garlic, potatoes, carrots, bell peppers, or yams are all great places to start.

Accommodate dietary restrictions by making it:

• Dairy-Free - Use your favorite plant-based milk, cheese, and butter substitutes.
• Gluten-Free - Use your favorite gluten-free pie dough recipe, or buy one from the store.

👩🏻‍🍳 Expert Tips

• Make the quiche dough up to a month in advance and pop it in the freezer. The night before you plan on baking it, place it in the refrigerator to defrost.
• Cook the squash and leeks and infuse the milk up to 3 days in advance.
• Cut down on prep time by opting for thin-skinned squash varieties (e.g. delicata or acorn) or frozen squash cubes.
• Soak your leeks after you slice them. I’m not sure why, but they are silt-magnets. Soak, drain, and rinse several times to prevent a sandy-tasting bite.

💭 Recipe FAQs

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