This rich and flavorful French Onion Tart recipe can be served as an appetizer, side dish or an entree. It features an incredible depth of flavor from cooking the onions until they’re fully caramelized. The french onion filling is spread into a homemade pastry and topped with Gruyere cheese to wrap it all up.
Easy French Onion Tart Recipe
This homemade onion tart is an impressive dish to make. I really love these sorts of savory pies and find myself turning to them for a special brunch, lunch or supper with friends. The trick to the depth of flavor is being patient and cooking the onions until they reach that perfect point of being deeply caramelized and sweet. How to make a simple savory French Onion Tart with a homemade pie crust:
- Crust – All purpose flour, salt, salted butter and cold water.
- French Onion Filling – Salted butter, garlic and 4 large yellow onions.
- Seasonings – Salt, sugar, black pepper and
- Herbs – Fresh thyme leaves plus additional for garnishing
- Balsamic vinegar.
- Cheese – Shredded gruyere or white cheddar cheese and chive and onion cream cheese.
- Dijon mustard.
- Egg wash – Large egg.
- Garnish – Grated or shredded Parmesan cheese.
How to Make the Best French Onion Tart Recipe
- Ingredients you’ll need to make homemade French Onion Tart: Yellow onions, butter, salt, granulated sugar, minced garlic, balsamic vinegar, fresh thyme, shredded Gruyere cheese, chive and onion cream cheese, Dijon mustard, one large egg beaten for the egg wash and grated or shredded Parmesan cheese.
- To make the Pastry Crust you’ll need: All purpose flour, butter, salt and cold water.
- Kitchen gadgets you’ll need: Mixing bowls, a pastry blender, measuring cups and spoons, sharp knife and cutting board, a large pot or skillet to cook the onions, a cheese grater and a sheet pan to bake the tart.
- This tart is somewhat like a savory galette popularly made with sweet pie and fruit fillings. It’s a free form pie and doesn’t require a special pan to bake it.
- When cooking the onions patience is key. Depending on how vigorously they cook it will change the amount of cooking time. Adjust according to the depth of color and flavor and once it’s achieved, they’re ready!
- Parchment paper will keep the tart from sticking to the pan and over browning.
- The french onions mixture for the filling can be prepared one day in advance and placed into an airtight container and chilled until assembling the tart to bake.
- When making the pastry, it’s important to allow it rest time to chill and firm the butter in the crust. Doing so will allow the butter to melt slowly while baking and create steam for a flaky texture and pleasing end result.
- You could use shredded or grated Parmesan cheese for sprinkling on the crust.
- I prefer the nutty flavor of Gruyere cheese for this recipe. That being said, you could adapt the flavor using a sharp white cheddar cheese or Asiago cheese. You could also use a cheese blend that you enjoy.
- Store leftover French Onion Tart wrapped in aluminum foil chilled in the refrigerator for up to 3 days.
- Reheat pieces in single servings in the microwave or on a sheet pan in a 350°F oven for a few minutes just until heated through. If it begins to brown lay a piece of aluminum foil on top.
More Savory Pies and Tart Recipes to Make
- Plum Tomato Tart is another option that has several severing options. Enjoy it as a lighter entree, side dish or appetizer.
- Bacon and Onion Bistro Tart was inspired by my favorite corner bistro from College.
- Fresh Tomato Tart with Basil Pesto and Fontina Cheese is packed with fresh summer flavors.
- Double Crust Chicken Pot Pie is comfort food 101.
- This recipe for Broccoli Cheese Quiche with Bacon forms its own crust while baking.
- Treat the family to a Chicken Pot Pie Crescent Ring for supper any day of the week.
- Beef and Potato Galette from A Foodie Affair.
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Helpful Kitchen Items:
French Onion Tart
- 1 1/2 cup all purpose flour
- 1/2 tsp salt
- 1/2 cup cold salted butter cubed
- 5-6 Tbsp cold water
- French Onion Filling:
- 4 Tbsp salted butter
- 4 large yellow onions thinly sliced
- 1 tsp salt
- 1 tsp sugar
- 1/2 tsp black pepper
- 1 Tbsp fresh thyme leaves plus additional for garnishing
- 1 medium clove garlic minced
- 2 Tbsp balsamic vinegar
- 2 cups shredded gruyere or white cheddar cheese divided
- 2 Tbsp softened chive and onion cream cheese
- 2 Tbsp dijon mustard
- 1 large egg lightly beaten
- 2 Tbsp grated Parmesan cheese
- To make the Crust: In a medium size mixing bowl, whisk together flour and salt. Using a pastry blender, cut the butter into the flour until the mixture is crumbly and the size of small peas. Drizzle in 5 tablespoons of water, stirring gently until everything is evenly moistened; add the final tablespoon of water if necessary to make a cohesive dough. Pat the dough into a disk, wrap in plastic wrap and refrigerate for 30 minutes.
- To make the Filling: Heat the butter in a large pot set over medium heat. Add the onions, salt, sugar, pepper, garlic and thyme. Cook uncovered, stirring occasionally, until the onions cook down by half and are golden brown and tender, about 35-45 minutes. Add the balsamic vinegar and stir to combine cooking just until evaporated. Remove from the heat and let cool.
- To assemble the Tart: Preheat the oven to 400°F line a large baking sheet with parchment, On a lightly floured work surface, roll the pie dough into a 12" circle. Trim edge lightly to make even, if needed. Transfer the dough to prepared parchment-lined baking sheet.
- Mix together Dijon and cream cheese. Spread on pie dough, leaving a 2-inch border. Sprinkle with 1 cup shredded cheese.
- Spoon cooled onions over cheese then sprinkle top with reserved 1 cup shredded cheese.
- Gently fold the outer edges of the dough over the filling to create a freeform crust. Brush the dough on all sides with the beaten egg then sprinkle Parmesan all over onions and crust.
- Bake for 30-40 minutes or until the dough is golden brown and set on the bottom.
- Let stand for 5-10 minutes, then slice into wedges and serve garnished with fresh thyme.