How to cook
Cut the cold and hard butter and add it into the flour. Add the salt and rub with your fingers, until crumbs are obtained. Beat the egg and use it to bring the crumbs together into a smooth ball of butter dough. If necessary, add a spoonful of cold water to make it easier.
Roll out the dough into a thin crust between two layers of baking paper. This is mandatory, so that it does not stick to the rolling pin.
Remove the top layer of paper and slide the other layer with the dough into a pan or tart tin with an approximate diameter of 80°F (26 cm). The edges should stick to the sides, forming a rim and a base for the stuffing. The dough itself can also be peeled from the bottom layer of paper, but there is a risk of tearing it, so if you do this, be careful and also grease the tin beforehand.
Chop the leeks and stew them, until they soften in the butter with a little salt. To make your savory tart finer, you can blend, so that a smooth cream is obtained.
Spread it evenly on the bottom of the base and grate the yellow cheese and crumble the blue cheese on top.
Beat the eggs with a pinch of salt and add the cream and milk to them. Season with black pepper and nutmeg and stir.
Pour the liquid mixture over the other products and shake gently, so that it reaches the lower layers.
Bake the savory tart with leeks and blue cheese in an oven heated to 370°F (190°C), until it aquires a golden brown color, for about 25 minutes.
Enjoy your meal!