I simply love a good French onion soup and I never make it at home. I rely on restaurants and not many serve it. This recipe makes me eager to try at home in the slow cooker. The picture alone is enough to make one drool!
Recipe & photo: allrecipes.com
In a large heavy pot, heat butter over medium-high heat; cook and stir onions until they become translucent, about 10 minutes. Sprinkle onions with sugar; reduce heat to medium. Cook, stirring constantly, until onions are soft and browned, at least 30 minutes. Stir in the garlic and cook until fragrant, about 1 minute.
Stir sherry into onion mixture and scrape bottom of pot to dissolve small bits of browned food from the pot. Transfer onions into a slow cooker and pour in the beef broth. Season to taste with sea salt; stir in thyme and bay leaf.
Cover and cook on LOW for 8 to 10 hours. About 10 minutes before serving, set oven rack about 8 inches from the heat source and preheat the oven's broiler. Arrange bread slices on a baking sheet.
Broil bread slices until toasted, 1 to 2 minutes per side.
Combine Gruyere, Emmental, Parmesan, and mozzarella cheeses in a bowl, tossing lightly. Fill oven-safe soup crocks 3/4 full of onion soup and float a bread slice in each bowl. Top with about 2 Tbsp. of cheese mixture per serving.
Place filled bowls onto a baking sheet and broil until cheese topping is lightly browned and bubbling, about 2 minutes.