This is a recipe for Caramelized Onion Tart with Gruyere Cheese. This combination of sweet and savory filling is heavenly. Balsamic vinegar, bacon and thyme make this an awesome savory tart to serve as an appetizer, or a light dinner with a simple tossed salad.
It’s late July in Colorado and that means I’m more excited to cook than any other time of year. Our Colorado fresh produce is starting to come in, fresh sweet corn, Rocky Ford Melons and Musso Farms is heralding the news that it’s Pueblo Chile Season.
I still have most of a bucket of Vidalia Onions in dark storage (back corner of my pantry) that I need to use before they go bad. And after all there are new Colorado onions to take their place now. I can’t think of a better way to use them than in this onion tart.
This onion tart recipe comes from the Pastry Kitchen at Cook Street Culinary School.
I love everything about this tart. The Vidalia onions become even more sweet with a long stove top sautee. And even more delicious cooking them with bacon and even more interesting with the addition of balsamic vinegar. Who can resist that combo of ingredients? Not us.
The seasoning for this onion is simple with fresh thyme. I used Lemon Thyme from my garden, but of course any fresh thyme will add a delicious note.
How to Blind Bake A Tart Shell:
I hope you’ll consider taking the time to make a homemade pie shell for this tart recipe. One of the great take-aways from Culinary School was how to make an All Butter Pie Crust. It’s really very easy and a skill I feel every home cook should learn. As French technique you’ll also see it referred to as pate brisee.
When making pies or tarts that call for a delicate filling a filling that’s already been cooked, you’ll need to blind bake the shell first, which simply means one pre-cooks the dough before adding the filling. That’s because the hour or so cooking time that it takes to bake the crust would over-cook some fillings, such as this onion tart filling.
- Simply place the dough into the pie or tart pan and gently form the dough to the shape of the pan. Then cover the dough with a round of parchment paper that’s been cut to size and place pie weights or dried beans in the parchment paper to hold the paper against the dough.
- Chill the crust for thirty minutes. I’ve even placed it in the freezer to make sure it gets nice and cold.
- Bake the pie dough in an oven preheated to 375 degrees for twenty minutes.
- Remove the pie from the oven, and lift out the paper and weights. Prick the bottom of the crust all over with a fork, to prevent bubbles. This is called docking.
- Return the crust to the oven and bake for an additional 15 to 20 minutes, until the crust is golden all over.
Now we’re ready to make this onion tart.
Recipe for Caramelized Onion Tart with Gruyere, Bacon and Thyme:
I’ve used a 9-inch tart pan for my recipe. You can also use an 8-inch pan for a thicker tart. Or even 8 individual 4″ to 5″ small tart pans.
I hope you give this Caramelized Onion Tart recipe a try. And if you do, please come back and let me know how you liked it and give the recipe a star rating.
Your feedback is valuable to me for developing future recipes. And if you have a favorite onion tart recipe, let me know, I’d love to give it a try.
Once I made my first tart, I became quite obsessed with making more and more. If you’re looking for more tart recipes, you won’t want to miss:
And if you’re looking for more tart or dessert recipes, don’t miss my dessert category. You’ll find both savory and sweet treats, including the most popular on my site for Caramelized Banana Ice Cream.
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Caramelized Onion Tart with Gruyere
- 1 Pie Crust preferably homemade – blind baked
- 3 large onions emincee’d (thin sliced)
- 3 ounces bacon fine diced (about 3 – 4 slices)
- 1 tablespoon sugar
- 1/2 teaspoon salt
- 2 teaspoons balsamic vinegar
- 2 tablespoons fresh thyme chopped
- fresh ground black pepper
- 1/4 cup heavy cream
- 1 cup gruyere grated
- Cook the bacon, stirring often, in a large non-stick fry pan over medium heat until mostly crisp. Remove onions to a plate and discard all but about 1 tablespoon of the grease.
- Reduce heat medium low. Add the onions, sugar and salt and cook, stirring often until they cook down by two thirds. About 10 minutes.
- Add the 2 teaspoons vinegar, reduce heat to low, and continue to cook until the onions are an even golden brown and softened, 15 – 20 minutes. (depending on the onions)
- Stir often and scrape up any brown bits clinging to the bottom of the pan. Watch the onions closely, you don't want them to burn, just to become golden and caramelized.
- Remove from heat, stir in the thyme and cooked bacon. Allow the ingredients to cool slightly. Taste, season with black pepper and add more salt if necessary.
- Preheat oven to 350 degrees. Stir the cream into the caramelized onions until thoroughly combined.
- Place the filling in a 9″ tart shell that’s been blind baked and spread it evenly with the back of a spoon. Sprinkle grated gruyere on top. Bake in oven until the filling is set, about 15 minutes.
- Serve warm or at room temperature. Garnish with a sprig of thyme.