Chop, process or mince the meat. Cook onion in the fat until soft. Add the meat and garlic, stirring well; then raise the heat so that the meat browns.
Turn it over in large sections with a spatula, so that it browns all over. Pour off any surplus fat.
Add some of the liquid and bubble gently for 5 minutes. Sprinkle on flour or cornstarch, stir again and add the remaining liquid.
Let it bubble to a rich sauce, adding the various flavorings to taste.
Meanwhile scrub, boil and peel the potatoes.
Set aside a couple and slice them thinly. Mash the rest with the milk and butter, seasoning to taste. Put the meat into a shallow dish.
Spread the mashed potato on top and, with the slices, make a ring around the edge. Scatter the cheese over, and brown under the broiler at a moderate heat, or at the top of a hot oven.
