Cheesy Caramelized Onion Tart
This Onion tart recipe is made with caramelized onions, a buttery crust, and creamy cheese to create a savory bake that’s perfect for gatherings or weeknight comfort.
golden, flaky crust filled with sweet caramelized onions and creamy cheese makes this onion tart a perfect dish for family dinners, brunches, or even as a party appetizer. It’s rich, savory, and satisfying without being heavy.
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This recipe takes a little time since you’ll prepare the shortcrust pastry and caramelized onions, but the end result is worth it. Serve it warm with a crisp salad for a light meal, or slice it into small squares for your next gathering.
If you are a true onion lover, be sure to copy my Best Caramelized Onion Dip Recipe!
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Ingredients Needed for Caramelized Onion Tart
For the crust:
- All-purpose flour – keep a light hand when mixing to avoid toughness.
- Butter – use salted or unsalted and keep it cold before cubing for a flaky crust.
- Egg
- Salt
- Cold water – add just enough for the dough to come together.
For the filling:
- Onions – thinly sliced into half-rings for even caramelization.
- Butter – unsalted or salted will work.
- Heavy cream – makes the filling rich!
- Eggs
- Cheese – we recommend a hard cheese like Parmesan, Gruyère, or Cheddar, all of which work well.
- Seasonings: Salt, black pepper, nutmeg.
How to Make a Flaky Onion Tart
Combine flour, salt, and butter in a large bowl. Rub together with your fingertips until crumbly.
Mix in the egg and a splash of cold water.
Knead gently into a smooth dough. Wrap and chill for 30 minutes.
In a skillet, melt butter over medium heat. Add onions and cook slowly, stirring often, until they turn golden and caramelized (about 20 minutes).
Whisk eggs and cream in a bowl. Add cheese, seasoning, and nutmeg. Stir until smooth.
Roll out the chilled dough and fit it into a 9-inch tart pan. Prick the base with a fork.
Cover with parchment and fill with pie weights or beans. Bake at 350°F for 10 minutes.
Spread the onions evenly in the crust, then pour the cream mixture over top.
Bake for another 25-30 minutes until the tart is golden and the filling is set.
Let cool slightly before serving warm or at room temperature.
Helpful Tips
- Chill the dough properly before rolling to prevent shrinkage during baking.
- Cook the onions slowly to bring out their natural sweetness without burning.
- For a lighter tart, swap half the cream with milk.
- Use freshly grated cheese for the best melting and flavor.
Substitutions and Variations
Cheese: Swap Gruyère for Swiss or Fontina, or use sharp Cheddar for a bolder flavor.
Onions: Try mixing red and yellow onions for a sweeter balance.
Crust: Use store-bought pie crust or puff pastry for a shortcut.
Herbs: Add fresh thyme or rosemary to the filling for a fragrant twist.
Vegetables: Stir in a handful of sautéed mushrooms or leeks with the onions.
How to Store
Leftover onion tart can be stored in the fridge for up to 3 days. Reheat gently in the oven.
Common FAQs
Yes, you can prepare the dough 1-2 days in advance and store it in the fridge, or freeze for up to 1 month.
Gruyère is classic, but Swiss, Fontina, or even a mix of Cheddar and Parmesan work beautifully.
Blind baking ensures the crust stays crisp and doesn’t get soggy from the filling. It’s highly recommended.
The filling should be golden on top and slightly firm to the touch. It will set more as it cools.
Yes, bake and cool the tart fully, then wrap and freeze. Reheat in the oven until warmed through.
This onion tart is the kind of dish that never goes out of style. Whether you’re hosting friends or just want a cozy dinner, it’s a flavorful choice that always impresses.
Easy Onion Tart
Ingredients
For the crust:
- 1 2/3 cups all-purpose flour
- 7 tbsp butter cold and cubed
- 1 egg
- Pinch of salt
- 1-2 tbsp cold water
For the filling:
- 3-4 yellow onions thinly sliced
- 2 tbsp butter
- 1/2 cup heavy cream
- 2 large eggs
- 1 cup grated hard cheese such as Gruyère, Parmesan, or Cheddar
- Salt and black pepper to taste
- Pinch of nutmeg optional
Instructions
- n a large bowl, mix the flour and salt. Cut in the butter until the mixture resembles coarse crumbs.
- Add the egg and just enough cold water to form a smooth dough. Shape into a ball, wrap, and chill for 30 minutes.
- While the dough chills, melt the butter in a skillet over medium heat. Add onions and cook, stirring often, until golden and caramelized, about 20 minutes.
- In a separate bowl, whisk together cream and eggs. Stir in grated cheese, salt, pepper, and nutmeg.
- Roll out the dough on a floured surface and fit into a 9-inch tart pan. Trim edges. Prick the bottom with a fork. Line with parchment and fill with pie weights. Bake at 350°F for 10 minutes.
- Remove parchment and weights. Spread caramelized onions over the crust, then pour the cream mixture on top.
- Return to the oven and bake 25–30 minutes, until the filling is golden and set.
- Let cool slightly before slicing. Serve warm or at room temperature.
Notes
- Caramelize onions slowly over medium heat for the best flavor.
- Blind baking is essential to prevent a soggy crust.
- This tart is delicious warm or chilled, making it great for leftovers.
