Make this recipe a recipe that people in that category can eat. categories: ['low_calorie'], recipe: heat butter and oil in heavy, large saucepan over medium heat. add onions, garlic and salt, and cook 5 minutes, stirring often. reduce heat to very low, and cook, stirring occasionally, 50 to 60 minutes, until onions are very tender and brown. stir in flour, and cook 3 to 4 minutes, stirring constantly. blend in broth, sherry and mustard. cover, and simmer 15 minutes, stirring occasionally. stir in sherry vinegar. preheat broiler, ladle soup into six heat-proof bowls. top each with slice of toast and grated cheese. broil until cheese is bubbly and golden, about 1 to 2 minutes. serve hot.

Target recipe: in a large skillet, sauté onions in butter until crisp-tender. transfer to an ungreased 5-quart slow cooker/crock pot. add the broth, worcestershire sauce, and bay leaves. cover and cook on low for 5 to 7 hours or until the onions are tender. discard bay leaves. top each serving with french bread and cheeses.