French Onion Soup Inspired Toast Cups

Preheat oven to 375°F (190°C). Grease a 4-6 cup muffin tin.

Using a rolling pin, slightly flatten each slice of bread. Press each slice into a muffin tin cup, shaping it to fit snugly. Bake for 8-10 minutes, or until lightly toasted and golden brown. Remove from oven and let cool slightly.

While the bread cups are baking, heat butter and olive oil in a large skillet over medium heat. Add sliced onions and cook, stirring occasionally, until softened and deeply caramelized, about 20-25 minutes. Reduce heat if onions start to burn.

Stir in brown sugar (if using) during the last 5 minutes of caramelizing. Deglaze the pan with sherry (or white wine, if using), scraping up any browned bits from the bottom of the skillet. Cook until the liquid is almost completely evaporated.

Remove from heat and stir in thyme, salt, and pepper to taste.

Spoon the caramelized onions into the toasted bread cups. Top each cup with shredded Gruyere cheese.

Pour about 2 tablespoons of broth into each cup, being careful not to overfill.

Bake for 8-10 minutes, or until the cheese is melted, bubbly, and lightly golden brown. Let cool slightly before serving.