Tarte aux oignons – Onion tart
Serves 4–5
Crust
100 g butter
100 g boiled and grated potato (var. Siikli)
100 g all-purpose flour
Filling
70 g slightly smoked pancetta or bacon diced
500 g onion
Salt, pepper and thyme
Egg and milk mixture
4 dl whole milk or milk/cream mixture
4 eggs
Swiss cheese, grated
Prepare the crust. It is well worth making a larger amount of crust in one go, because it keeps well in the freezer and can be used in both sweet and salty pies and tarts. Boil the potatoes in their skins the day before. Peel and grate the cold potatoes. Weigh the accurate amounts of grated potato, butter and flour. Combine the ingredients with your hands to a smooth dough. Roll it out to a circle and line a tart pan with the dough. Prebake in oven (180 ºC) until half done.
Prepare the filling. Cook the pancetta or bacon. Slice the onions and cook them with the bacon until soft. Season with salt, pepper and thyme. Spread the filling into the prebaked crust. Combine milk and eggs and pour over the filling. Finish with a little grated cheese on top. Cook in the oven (180 ºC) for about 40 minutes until the egg/milk mixture has set. Serve the onion tart hot or cold.