Prepare the egg spaetzle according to the instructions on the packet. Cut the leek into rings and fry together with the minced meat. Add the sour cream and herbs to the pan with the minced meat and leek and mix, season to taste with salt and pepper. Mix the spaetzle with the minced meat sauce and place in a baking dish. Cover with cheese and bake at 200 degrees for about 25 minutes, until the cheese is burned golden brown.