Caramelised Onion Tart

Delight your taste buds with this elegant Caramelised Onion Tart, a perfect balance of sweet, savory, and buttery goodness. Featuring a flaky homemade pastry crust, this tart is generously layered with golden, slow-cooked caramelised onions enhanced by a hint of balsamic vinegar, brown sugar, and fresh thyme. Topped with creamy crème fraîche and nutty Gruyère cheese, it bakes to perfection for a golden, bubbly finish. Whether you're hosting a sophisticated brunch or craving a comforting yet refined dinner, this tart is an irresistible crowd-pleaser. Simple ingredients, bold flavors, and a rich, caramelized twist make every bite unforgettable. Perfect for entertaining or a cozy night in, this easy yet stylish recipe is sure to impress!

Nutriscore Rating: 50/100

Prep Time:30 mins

Cook Time:40 mins

Total Time:70 mins

Servings: 6

Ingredients

• 200 grams all-purpose flour
• 100 grams unsalted butter
• 3 tablespoons cold water
• 2 tablespoons olive oil
• 4 medium onions (thinly sliced)
• 1 tablespoon balsamic vinegar
• 1 tablespoon brown sugar
• 1 teaspoon fresh thyme leaves
• 1 teaspoon salt
• 0.5 teaspoon black pepper
• 100 grams crème fraîche
• 100 grams grated Gruyère cheese
• 1 unit egg yolk

Directions

Step 1

Preheat your oven to 190°C (375°F).

Step 2

To make the crust, combine the all-purpose flour and a pinch of salt in a bowl. Add the unsalted butter, and use your fingertips to rub it into the flour until the mixture resembles breadcrumbs.

Step 3

Stir in the cold water, one tablespoon at a time, until the dough comes together. Form it into a disc, wrap in cling film, and refrigerate for 15 minutes.

Step 4

While the dough chills, heat the olive oil in a large pan over medium heat. Add the sliced onions and cook for 15-20 minutes, stirring occasionally, until softened and golden brown.

Step 5

Stir in the balsamic vinegar, brown sugar, thyme leaves, salt, and black pepper. Cook for another 2-3 minutes until the onions are glossy and caramelised. Remove from heat and set aside to cool slightly.

Step 6

Roll out the chilled dough on a floured surface to fit a 9-inch tart tin. Transfer the dough to the tin and press it into the edges. Trim any excess dough.

Step 7

Prick the base of the pastry with a fork, line it with baking parchment, and fill with baking beans or rice. Blind bake for 10 minutes, then remove the parchment and beans, and bake for another 5 minutes.

Step 8

Allow the crust to cool slightly. Spread the crème fraîche evenly over the base of the tart.

Step 9

Top with the caramelised onions and sprinkle with the grated Gruyère cheese.

Step 10

In a small bowl, beat the egg yolk and brush it over the edges of the tart crust for a golden finish.

Step 11

Bake in the preheated oven for 15-20 minutes, or until the cheese is melted and bubbly, and the crust is golden brown.

Step 12

Remove from the oven and let cool for 5 minutes before serving. Slice into portions and enjoy!

Nutrition Facts

Serving size	(1022.0g)

Amount per serving	% Daily Value*
Calories	2768.2

Total Fat 192.7g	0%
Saturated Fat 103.1g	0%
Polyunsaturated Fat 2.7g
Cholesterol 615.9mg	0%
Sodium 3118.7mg	0%
Total Carbohydrate 206.2g	0%
Dietary Fiber 12.6g	0%
Total Sugars 32.3g
Protein 57.4g	0%

Vitamin D 38.2IU	0%
Calcium 1105.6mg	0%
Iron 11.7mg	0%
Potassium 1076.6mg	0%

*The % Daily Value tells you how much a nutrient in a serving of food contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.

Source of Calories

Fat: 62.2%

Protein: 8.2%

Carbs: 29.6%