2 tbl butter or margarine
2 lbs sweet onions (such as Vidalia or Maui), sliced 1/4" thick
1/2 tsp salt
black pepper to taste
2 tbl raspberry vinegar
1/2 c. black currant or raspberry jam (reduced sugar is OK)
Melt the butter in a large nonstick skillet over medium heat. Add the onions, salt, and black pepper, toss to coat the onions. Cover and cook 10 min, stirring occasionally. If the onions seem to dry out, sprinkle a few drops of water in the skillet.
Uncover and cook another 30 min, or until the onions are brown and soft. Add the vinegar and jam and cook for 5 min, to melt the jam.