Tomato, Basil & Caramelized Onion Quiche

Tomato, Basil & Caramelized Onion Quiche on a striped linen with basil
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Combining a creamy egg custard with heirloom tomatoes, fresh basil, a shaving of Parmigiano-Reggiano, and onions caramelized to the point of utter umami sweet/savoriness, this is the be-all end-all of quiche recipes. 

Mary, Mary Quite Contrary, How Does Your Garden Grow?

Several years ago, we attended a lecture with the founder of the Slow Food Movement, Carlo Petrini. In his speech, he said something we’ll never forget: “I remember when a tomato used to taste like a fruit.” Simple, perhaps, but something about that stuck, and each summer when heirloom tomatoes reach their sunkissed peak, we always come back to Signore Petrini. Of course, sun-sweetened tomatoes are delicious any which way you slice it, but for us, we love to enjoy their juicy pop in a tomato quiche. Add garden-fresh basil, sweet caramelized onions, and a shaving of Parmigiano-Reggiano and you get our Heirloom Tomato Quiche with Caramelized Onions, Basil, and Parmigiano-Reggiano. Basically, the summertime breakfast quiche to end all breakfast quiches. Peak summer, peak quiche—it’s all of the things. 

a bowl of heirloom tomatoes slices and basil and parmesan cheese and garlic on a cutting board

What Is Quiche?

Our definition of “quiche” is simply a savory pie crust (aka, pate brisse) filled with an eggy custard. For food history buffs, here’s a tasty tidbit: quiche originated in the Alsace-Lorraine region of France, and it’s most popular iteration—Quiche Lorraine—is filled with bacon, Gruyère cheese, and heavy cream. We’ve taken that classic quiche recipe and transformed it into a vegetarian celebration of all things summer. Here’s how:

  • We’ve swapped quiche Lorraine’s classic bacon for umami-rich caramelized onions.
  • Add summertime seasonal ingredients like juicy heirloom tomatoes and fragrant, fresh basil.
  • Sprinkle with freshly grated Parmigiano-Reggiano. 
Tomato, Basil & Caramelized Onion Quiche styled with tomatoes and a linen

Can You Freeze Quiche?

Yesssssss!! Maybe your friend just had a baby, or your tomato plant is so weighted down with burtingly ripe tomatoes it can barely stand upright. No matter the reason, bake this egg quiche ahead of time, let completely cool, then wrap tightly in a few layers of cling wrap, and freeze. When you’re ready for a little slice of summer—and this heirloom tomato quiche is perfect for that—simply pop the still-frozen quiche in a preheated oven at 350°F for about 15-20 minutes, or until it is heated through. 

Frittata vs. Quiche—What’s the Diff?

The easiest way to remember? Quiche = crust. Frittatas typically omit the crust and heavy cream, relying mostly on the eggs. And a tart is something different altogether—it’s commonly made without any egg filling (but does have a crust —are you confused yet?). All three are delicious in their own right (a good tomato tart recipe is worth all the ripe tomatoes), but today we’re pie-eyed for this tomato basil quiche recipe. 

How to Make Quiche

Our quiche recipe is pretty much foolproof, thanks to the fact that most of the mixing happens in your trusty food processor. Adding caramelized onions is an easy way to add tons of flavor, while still making this a vegetarian quiche recipe. 

  • Start by adding thinly sliced onions to a hot frying pan bubbling with butter and brown sugar and cooking down until the onion slices collapse onto themselves and take on a deep, dark mahogany hue. 
  • While the onions caramelize, make the quiche crust by pulsing together flour, salt, and frozen butter in your food processor. Add water at a slowwww trickle until the dough just comes together. The more water you add, the more the crust will shrink when it bakes, so less water the better. 
  • Layer your heirloom tomatoes, cheese, fresh basil, and sweet caramelized onions into the crust. Pour in eggs and fresh cream, and bake until the center loses its wobble!
  • Serve your tomato-laden, caramelized onion quiche alongside our Simple Butter Lettuce salad and call it breakfast well done (or dinner, if you please!). 

Tools You’ll Need to Make This Easy Quiche Recipe:

  • Sharp knife
  • Food processor. Ours sees so much action we stopped even trying to put it away. Now it just lives in its happy little place on our counter, and honestly we don’t mind one bit.
  • Quiche pan or pie pan. You don’t have a quiche pan?! Not to worry—a regular 8- or 9-inch pie pan will do. 
Tomato, Basil & Caramelized Onion Quiche on a plate with striped linen

Love Eggs? Here Are More Eggy Recipes We Love:

Seriously, we could eat eggs for every meal of the day. You, too? Take these egg recipes out for a spin:

  • Homemade tomatillo sauce gives our Salsa Verde Baked Eggs the perfect amount of fresh jalapeno heat. 
  • Deconstructed breakfast tacos—aka Migas—are totally a thing. 
  • The only thing better than a classic BLT? Our Heirloom BLT with Pesto, topped with a runny fried egg.

Best Quiche Recipe, Ever? 

Show us how yours turned out and tag us @themodernproperand #themodernproper.

Tomato, Basil & Caramelized Onion Quiche

Serves 8

Filling

1 small sweet onion, halved and thinly sliced
1 tbsp butter
1 tsp brown sugar
6 large eggs
3/4 cup heavy cream
1 tsp salt
1/2 tsp fresh ground black pepper
2-3 oz Parmigiano-Reggiano cheese finely grated
1 medium heirloom tomato, chopped
2 garlic cloves, minced
1 handful of basil leaves, thinly sliced

Crust

1 1/2 cup all purpose flour
9 tbsp unsalted butter, cold, 1/2 inch diced
1/2 tsp salt
3 1/2 tbsp ice water

Method

  1. Before preparing quiche filling, dice 9 tablespoons of butter, place on parchment paper and put in freezer.
  2. Melt the remaining butter in a small frying pan over medium-low heat until foaming. Add the onions and sugar, let them cook, stirring occasionally, until they are deep golden brown and caramelized, about 40 minutes. Add garlic to the pan and let them cook 5 minutes longer. Season well with salt and pepper, remove from the pan, and let cool.
  3. While onions are caramelizing, place flour and ½ teaspoon salt into a food processor with fitted blade. Pulse to combine. Add the butter from the freezer. Pulse 8 to 12 times, until the butter is the size of peas. With the machine running, pour the ice water down the feed tube and pulse the machine until the dough begins to form a ball. Dump out on a floured board and roll into a ball.
  4. Preheat oven to 375º F.
  5. While onions are cooling, press dough into an 8 or 9 inch pie or quiche pan. Place in refrigerator while preparing the eggs.
  6. Combine eggs, cream, salt and pepper in a food processor or blender. Blend the ingredients for 1 minute. Layer the tomatoes, cheese and basil in the bottom of the crust lined quiche pan. Evenly disperse onion and garlic over top, then pour the egg mixture on top of that. Bake for 35-45 minutes until the egg mixture is set. Cut into 8 wedges.