Wash the leek and cut into rings. Heat the lard in a saucepan, sauté the smoked meat together with the leek and sauté for another 5-10 minutes.
In the meantime, grease a 26 springform pan or quiche pan. Pour in the puff pastry and form an edge. Prick the base of the puff pastry several times with a fork.
Mix the eggs, milk, cream and mountain cheese together and add to the leek. Mix well once and pour into the mold. Put the quiche in the preheated oven. Bake on the middle shelf at approx. 200 ° C for approx. 30 minutes. If you prefer it darker, you can leave the quiche in the oven for 15 minutes longer.
Then take the quiche out of the oven and let it cool down a little so that you don`t burn your tongue too much.