Name: French Onion Tart
Prep time: 40 min
Cook time: 40 min
Total time: 80 min
Cuisine: French
Ingredients: 2 cups all-purpose flour.; ½ teaspoon kosher salt.; 1 tablespoon sugar.; 12 tablespoons cold unsalted butter, diced (1 ½ sticks).; ½ cup ice water.; 1 cup Gruyère cheese, shredded (4 oz).; 1 ½ teaspoons fresh thyme, minced.; 2 teaspoons fresh chives, minced.; 1 ¼ lbs sweet onions (about 3 medium onions).; 1 tablespoon heavy cream.; 3 tablespoons unsalted butter, diced.; 1 teaspoon kosher salt.

This savory French Onion Tart combines a golden, flaky crust with thinly sliced sweet onions, Gruyère cheese, and fresh herbs like thyme and chives. It’s the perfect dish to serve at brunch, lunch, or a light dinner. The balance of caramelized onions and melted cheese creates a rich and flavorful tart that pairs wonderfully with a side salad. Serve warm or at room temperature for a delightful French-inspired meal that’s sure to impress.

If you're in the mood for something savory and sophisticated, this French Onion Tart is the perfect choice. Made with thinly sliced onions, Gruyère cheese, and fresh herbs, this tart is a delicious twist on a classic French dish.

INGREDIENTS

All-Purpose Flour: 2 cups, for making the tart crust.
Kosher Salt: ½ teaspoon, to season the crust and the tart.
Sugar: 1 tablespoon, to add a touch of sweetness to the crust.
Cold Unsalted Butter: 12 tablespoons (1 ½ sticks), diced, for a flaky crust.
Ice Water: ½ cup, to bring the dough together.
Gruyère Cheese: 1 cup, shredded, for a rich, cheesy layer.
Fresh Thyme: 1 ½ teaspoons, minced, to add herbal notes to the tart.
Fresh Chives: 2 teaspoons, minced, for added flavor.
Sweet Onions: 1 ¼ lbs (about 3 medium onions), thinly sliced for the filling.
Heavy Cream: 1 tablespoon, to brush on the onions before baking.
Unsalted Butter: 3 tablespoons, diced, to add richness to the tart.
Kosher Salt: 1 teaspoon, to season the onions and the crust.

INSTRUCTIONS

Step 1:: Combine the flour, kosher salt, and sugar in a food processor or a large bowl. Add the diced butter and process until the mixture resembles coarse crumbs.
Step 2:: Gradually add the ice water, processing or mixing until the dough comes together. Wrap the dough in plastic wrap and refrigerate for at least 30 minutes or freeze for later use.
Step 3:: Peel, halve, and thinly slice the sweet onions into half moons, keeping the slices intact.
Step 4:: Roll the dough into a 10 x 14 inch rectangle and place it on a parchment-lined sheet tray.
Step 5:: Arrange the onion half moons on the pastry in diagonal lines, just barely overlapping. Sprinkle the shredded Gruyère cheese right to the edges of the pastry, followed by the minced thyme and chives.
Step 6:: Brush the onions lightly with heavy cream, dot the top with the diced butter, and sprinkle with kosher salt.
Step 7:: Bake the tart in a preheated oven at 400°F (200°C) for about 40 minutes, or until the tart is golden brown and the onions are fully cooked. Cover the edges with foil if they brown too quickly.
Step 8:: Let the tart cool slightly before cutting into squares, strips, or wedges. Serve warm or at room temperature.

Serving and Storage Tips

Serve the tart warm or at room temperature, cut into squares, strips, or wedges.
This tart pairs beautifully with a light side salad or a glass of white wine for a French-inspired meal.
Store any leftovers in an airtight container in the refrigerator for up to 3 days.
Reheat in the oven at 350°F for 10-12 minutes to restore its crispiness.

Helpful Notes

For added flavor, try caramelizing the onions before layering them on the tart.
Gruyère cheese provides a rich flavor, but feel free to substitute it with Swiss or Emmental cheese if preferred.

Tips from Well-Known Chefs

Chef Julia Child suggests chilling the dough thoroughly before rolling it out to ensure a flaky crust.
Ina Garten recommends using high-quality butter for the crust to achieve the best texture and flavor.
Gordon Ramsay advises adding a dash of balsamic vinegar to the onions for an extra depth of flavor.

WHY YOU'LL LOVE THIS RECIPE

This tart is a perfect balance of rich, savory flavors and a crisp, buttery crust.
It’s a great dish to serve as an appetizer, for brunch, or as a light dinner.
The combination of fresh herbs, sweet onions, and Gruyère cheese makes this tart irresistibly flavorful.

VARIATIONS

Add sautéed mushrooms or caramelized leeks to the tart for an extra layer of flavor.
For a meatier option, add crumbled bacon or pancetta to the onion filling.
Try a puff pastry base for a lighter, flakier tart crust.