Cut the cabbage in half and cut out the stalk and the coarse outer leaves; cut the cabbage halves into strips.
Peel and slice the onions and lemon.
Place the prepared cabbage, onions and lemon in a pan with 4 1/2 pints water.
Add the salt, bay leaf, cloves and sugar.
Bring to the boil, cover and simmer for 30 minutes.
Melt the butter, stir in the yogurt and allow to heat through, but do not boil.
Drain the cabbage mixture and place in a serving dish.
Pour over the yogurt sauce.
Serve with broiled or fried pork chops.