2 tablespoons olive oil
2 cups slivered onions
1 teaspoon dried oregano
1/4 cup cider vinegar or red wine vinegar
2 15-ounce cans red kidney beans, rinsed and drained
1 teaspoon coarse salt (kosher or sea salt), or to taste – optional
1 cup chopped Italian (flat-leaf) parsley
1/4 cup pimento-stuffed olives, sliced in half
Heat olive oil in a large pot over medium heat. Add onions; saute for 5 minutes. Add oregano, vinegar and beans. Cook over low heat until beans are warm.
Remove from heat and stir in salt, parsley and olives. Serve warm or at room temperature.