Ingredients:

For the crust (pie crust):

– 1 cup, 5.3 oz, 150g flour
– 5 tblsps, 75g butter
– 1/2 teaspoon salt
– 1/2 cup, 12 cl water

For the onions:

– 1 cup, 25 cl sour cream
– 1/2 cup shredded French gruyere cheese (emmental)
– 2 eggs
– 4 onions
– 1/4 cup, 5 cl water
– 1 pinch of salt and pepper

Preparation:

For the crust:

– Combine flour, salt, butter, and water in a bowl. Mix with your fingers until the dough clumps.
– Put aside in the refrigerator at least an hour.

For the onion:

– In a large sauté pan, put the onions with 1/4 cup of water.
– Cook until the onions get caramelized at medium heat.

– In a large bowl, mix sour cream and eggs.
– Add salt and pepper.
– Whisk until smooth.

– Stir in the onions and half of the gruyere cheese into the mix.

– Lay down the dough and place it into a tart pan (12-inch diameter).
– Pour the onion sauce into the crust and sprinkle the remaining gruyere cheese on top.

– Bake at 400°F (200°C) for 25 minutes in a pre-heat oven. This is what you should get:

You might serve the onion tart with green salad. It is delicious!