Knead the flour, butter in flakes, 1 egg and 1/4 teaspoon of salt into a smooth short pastry. Wrap in foil and chill for about 30 minutes. In the meantime clean, wash and cut leek into rings.
Cook the leek in boiling salted water for about 5 minutes, drain. Wash the smoked pork loin, dab dry and cut into cubes of about 2 cm. Heat the oil and fry the smoked pork loin for about 3 minutes, turning it over.
Season with pepper. Grate cheese. Grease an ovenproof dish (approx. 20 x 30 cm). Roll out the dough to a square on a lightly floured work surface and place in the baking dish. Cut off any excess dough and form into a ball again.
Press the edges of the dough. Prick the dough base several times with a fork. Refrigerate again for about 20 minutes. In the meantime roll out the remaining ball of dough again. Cut out small cookies. Put them on a baking tray lined with baking paper.
Separate 1 egg. Whisk egg yolk and cream. Spread the cream on the cookies. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 5-7 minutes. Whisk milk, 3 eggs and egg white.
Season with salt, pepper and nutmeg. Mix leek and pork loin, fill into the casserole dish. Pour over the egg milk and sprinkle with cheese. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 40 minutes.
Cut the cress short and sprinkle on top. Serve the casserole garnished with cookies.