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To make this tasty meal, gather these simple ingredients:

Gooey French Onion Grilled Cheese

Upgrade your lunch with this irresistible Gooey French Onion Grilled Cheese! Combining rich, melty cheeses with sweet caramelized onions, this recipe promises comfort and flavor in every bite. Perfect for a cozy meal, learn step-by-step how to create your new favorite sandwich. Explore tips for achieving maximum gooeyness and customizations to suit your taste. Click through to uncover the full recipe and make this delightful dish today!
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Ingredients
  

4 slices of sourdough bread

2 tablespoons unsalted butter

2 medium onions, thinly sliced

1 teaspoon sugar

1 teaspoon balsamic vinegar

1 cup shredded Gruyère cheese

½ cup shredded mozzarella cheese

2 tablespoons fresh thyme leaves

Salt and pepper to taste

Optional: 1 tablespoon Dijon mustard for extra flavor

Instructions
 

In a large skillet, melt 1 tablespoon of butter over medium heat.

    Add the sliced onions, sprinkle with sugar, and sauté for about 10-15 minutes, stirring occasionally until they are caramelized and soft.

      Stir in the balsamic vinegar and season with salt and pepper. Remove from heat and set aside.

        In another bowl, mix together the Gruyère and mozzarella cheeses.

          Heat a separate non-stick skillet over medium-low heat. Spread a thin layer of butter on one side of each slice of sourdough bread.

            Place two slices of bread, butter-side down, in the skillet.

              Layer half of the cheese mixture on top of the bread in the skillet, followed by the caramelized onions, thyme leaves, and the remaining cheese mixture.

                Top with the other two slices of sourdough bread, butter-side up. Cook for about 3-4 minutes until golden brown.

                  Carefully flip the sandwiches and cook for another 3-4 minutes, pressing down slightly with a spatula until the cheese is melted and the bread is crispy.

                    If using Dijon mustard, spread it on the inside of the bread before adding the cheese for extra flavor.

                      Remove the sandwiches from the skillet, slice in half, and serve immediately.

                        Prep Time, Total Time, Servings: 10 minutes | 30 minutes | Serves 2