- 2 tbsp. unsalted butter, divided
- 1 large yellow onion, halved and thinly sliced
- Pinch of sugar
- Kosher salt and freshly ground pepper, to taste
- ¾ tsp. minced fresh thyme leaves
- Splash of dry white wine*
- 4 baguette slices, cut on an extreme diagonal for maximum surface area
- Thinly sliced Gouda cheese (about 2 oz.)
- Thinly sliced Gruyere cheese (about 2 oz.)
- 1 clove garlic, peeled
*Feel free to substitute red wine or beef broth if desired
1. To make the caramelized onions, melt 1½ tablespoons of the butter in a 12-inch skillet over medium heat. Add the sliced onions to the pan with the sugar, salt and pepper. Stir well. Reduce the heat to medium-low. Cook the onions, stirring occasionally, until golden brown and fully caramelized, about 15-20 minutes. Stir in the thyme and cook until fragrant, about 1 minute. Increase the heat to medium-high. Pour in the splash of wine and continue to cook, stirring frequently, until most of the liquid has cooked off. Remove from the heat and set aside.
2. To assemble the sandwiches, layer two baguette slices with a good portion of the caramelized onions. Top with the sliced Gouda and Gruyere cheeses, and top with the remaining baguette slices. Heat another skillet over medium-high heat and melt the remaining ½ tablespoon of butter. Add the sandwiches to the pan and grill, turning once, until the bread is lightly browned and the cheese is melted. (Lower the heat if the sandwiches are browning too quickly.) Before serving, slice the clove of garlic in half and rub the cut side of the clove over the surface of the baguette slices. Serve immediately.