Tart with Brie and Caramelized Onions

Directions

1. 1

   Step 1

   

   Sift the flour. Place the butter in the freezer for 10–15 minutes. Wash the leek and thyme. Prepare a mixer, a pan, a 24 cm tart pan, as well as plastic wrap, a sheet of parchment paper, and a weight.

2. 2

   Step 2

   

   Grate 100 g of butter into a bowl with the flour. Knead everything with your hands until you get a uniform, moist crumb. Add 1 egg, salt, and 1 tbsp of water to the crumbs.

   TipWork quickly so the butter doesn't melt from the warmth of your hands.

3. 3

   Step 3

   

   Mix all the ingredients and gather the dough into a ball. Wrap the dough in plastic wrap and refrigerate for 30 minutes.

4. 4

   Step 4

   

   Slice the white part of the leek into thin rings. Combine 20 g of butter and 1 tbsp of olive oil in a pan. Let the mixture heat over medium heat. Add the leek to the pan. Sprinkle in a pinch of salt.

5. 5

   Step 5

   

   Sauté the leek for 25 minutes, stirring occasionally. When the leek becomes soft and takes on a pleasant caramel hue, add the sugar and vinegar. Increase the heat, stir, and cook for another 3–4 minutes.

6. 6

   Step 6

   

   Preheat the oven to 180 °C. Grease the tart pan with the remaining butter. Roll out the dough into a sheet and press it into the pan, forming the edges. Make a few pricks with a fork to prevent the dough from puffing up.

7. 7

   Step 7

   

   Line the dough with parchment paper and place a weight on top, such as beans or other legumes. Bake the base with the weight for 10–12 minutes at 180 °C.

8. 8

   Step 8

   

   Whisk the eggs for the custard with the sour cream until smooth. Add the caramelized onions, mustard, and a pinch of salt. Mix.

9. 9

   Step 9

   

   Remove the pan from the oven and carefully remove the weight. Pour the custard over the dough. Slice the cheese thinly and arrange it on top. Bake the tart for another 25–30 minutes at 180 °C. The tart should brown, and the filling should become firm.

10. 10

    Step 10

    

    Let the tart cool in the pan, then slice it into pieces.