Heat oil in heavy large pot over medium heat. Add onions and dried red pepper. Cover and cook until onions are tender, stirring occasionally, about 15 minutes. Add brown sugar, vinegar, sherry and ginger. Cook uncovered until onions are very tender and mixture is thick, stirring frequently, about 20 minutes. Add raisins and cook until mixture is very thick and dark, stirring frequently, about 20 minutes. Season to taste with salt and pepper. Cool completely. (Can be prepared 4 days ahead. Cover and refrigerate.)
Stovetop