Peel the beets, then slice them into thin circles.
Heat the butter/margarine with the sugar and vinegar in a wide saucepan. When the butter has melted, add the beets, stir gently, cover and gently simmer for 20 minutes. Add the raisins and cook for another 10 minutes, stirring occasionally.
Meanwhile, using a sharp knife score the skin in a diagonal direction being careful not to cut through to the meat. Place skin side down in a dry, hot pan and fry for 8-10 minutes at low temperature. Cook on the other side for 2-4 minutes ( longer, if you like it well cooked).
Transfer them onto a plate and rest for 5 minutes.
Arrange the beet & raisin mixture in 4 serving plates.
Serve warm.