Description
This caramelized onion tart features a rich, buttery crust filled with sweet, deeply caramelized onions and creamy Gruyere cheese. A perfect savory tart that balances a tender, flaky pastry with a luscious, cheesy onion filling, ideal as an appetizer or light meal.
Ingredients
For the Crust
- 1 ¾ Cup All Purpose Flour
- ⅔ Cup Unsalted Butter (Cold)
- 1 Pinch Salt
- 1 Egg Yolk
- 1 to 3 Tablespoons Cold Water
For the Filling
- 3-4 Onions (Around 7 Cups, Thinly Sliced)
- ¼ Cup Butter
- 1 Tablespoon Water
- 2 Tablespoons Flour
- ½ Cup Milk
- 1 Cup Shredded Cheese (Gruyere preferred)
- Salt and White Pepper to Taste (Or Black Pepper)
Instructions
- Prepare the dough: Place cold butter and flour in a food processor. Pulse until the mixture resembles breadcrumbs. Alternatively, use a pastry cutter or two forks to cut the butter into the flour.
- Combine wet ingredients: Stir in the egg yolk and 1 tablespoon of cold water. Add 1-2 additional tablespoons of water if the dough doesn’t come together easily.
- Form and chill dough: Form the dough into a disc, cover with plastic wrap, and chill in the refrigerator for 30 to 60 minutes to firm up.
- Roll out dough: On a lightly floured surface, roll the dough out to about ¼ inch thick. Press it into a 9-inch pie or tart pan. Refrigerate for about one hour or freeze for 20-30 minutes to set the shape.
- Preheat oven: Set the oven to 425°F (220°C) for the blind baking.
- Caramelize onions: Heat ¼ cup butter in a large skillet over medium heat. Add thinly sliced onions and a pinch of salt. Cover and cook for 5-10 minutes, then cook uncovered, stirring occasionally, for an additional 15-20 minutes until onions are deeply caramelized.
- Make the filling sauce: Deglaze the pan with 1 tablespoon of water, scraping up any browned bits. Sprinkle in 2 tablespoons of flour and stir to combine. Gradually add ½ cup milk, stirring to make a smooth sauce. Cook for 1-2 more minutes, then season with salt and white or black pepper to taste.
- Blind bake crust: Poke holes in the tart dough with a fork to prevent puffing. Blind bake the crust in the preheated oven for about 10 minutes until it starts to set.
- Assemble tart and bake: Pour the caramelized onion filling into the partially baked crust, sprinkle 1 cup shredded Gruyere cheese over the top. Reduce oven temperature to 350°F (175°C) and bake for 15-20 minutes or until the filling is set and the cheese is melted and lightly golden.
Notes
- Use cold butter to ensure a flaky and tender crust.
- Caramelizing onions takes time; low and slow cooking helps develop deep flavor.
- If preferred, black pepper can substitute white pepper.
- Gruyere cheese adds a nutty, creamy taste but any good melting cheese like Emmental or sharp cheddar can be used.
- Chilling the dough before blind baking prevents shrinking and helps maintain shape.
