Cut the meat into 2 inch lengths and about 1 inch thick. Season with salt and pepper and brown in 3 to 4 ozs. of butter or lard. Add the gammon, cut in small cubes, and brown. Remove the meat and the gammon from the saucepan, pour out most of the melted butter or lard, leaving about 2 tablespoons of it in the saucepan. Stir in 2 tablespoons of flour to make a light brown roux. Add gradually the bottle of beer, stirring continuously. Shred or chop the onions, and brown in lard. Pour the sauce made with the beer in a casserole, and fill with alternate layers of browned onions, meat and gammon, add the chopped garlic, the sugar, season with salt and pepper, cover the casserole, bring to the boil, and simmer very gently in the oven for 2½ to 3 hours. It may be necessary to add more beer, as the meat, etc., should be well covered with the liquid. Just before serving, a little vinegar is added, and the whole is served in a somewhat deep dish. Plain boiled potatoes invariably accompany the Flemish carbonnade, as they help to “mop” up the delicious sauce.