Slow Cooker Onion Soup

¼ cup butter, melted

1 large sweet onion (such as Vidalia®), cut into thin slivers

1 small red onion, cut into thin slivers

2 cloves garlic, minced

4 cups beef stock

3 tablespoons brandy

2 teaspoons soy sauce

2 teaspoons Worcestershire sauce

salt and ground black pepper to taste

2 cups Italian-style seasoned croutons

3 slices provolone cheese

Melt butter in a skillet over medium heat; cook and stir sweet onion and red onion in melted butter until softened, about 10 minutes. Cook and stir garlic into onion mixture until fragrant, about 2 minutes. Transfer to a slow cooker.

Pour beef stock, brandy, soy sauce, and Worcestershire sauce into slow cooker. Season with salt and black pepper.

Cook soup on High for 4 to 5 hours.

Preheat the oven s broiler and set the oven rack about 6 inches from the heat source.

Ladle the soup into 3 oven-proof bowls; top with croutons and a slice of Provolone per bowl.

Broil in the preheated oven until cheese melts and begins to brown, about 3 minutes.