Use ground lamb for a Shepherd`s Pie and ground beef for the Cottage Pie.
Heat the fat in the saucepan, add 1 large chopped onion, fry the mince for about 3 minutes, add flour, roast and stir well. Pour in almost 1/4 liter of stock and simmer while stirring, season with pepper, salt, mustard and ketchup.
Grease a baking dish and add the mince.
Cook the potatoes in salted water until cooked, drain and mash them with 30 g butter and warm milk to a firm pulp.
Carefully place on the minced meat and draw a pattern (plowed field) over it with a fork. Put a few more flakes of butter on the mashed potatoes and sprinkle a little salt over them.
Preheat the oven and bake at 200 ° C for 20-30 minutes, then let it turn golden yellow at 180 ° C in approx. 20 minutes.