Blackberry & Gruyère Grilled Cheese with Caramelized Onions

Ingredients:

• 8 slices of whole grain bread (four sandwiches)
• 4 Tbsp. unsalted butter, softened
• 8 oz. Gruyère cheese, grated
• 1/2 cup fresh blackberries, slightly mashed
• 1 large red onion, thinly sliced
• 2 Tbsp. balsamic vinegar
• 1 Tbsp. brown sugar
• 1 Tbsp. olive oil
• 1/2 tsp. salt
• 1/2 tsp. freshly ground black pepper
• 1/4 cup fresh basil leaves, washed and dried

Instructions:

1. In a medium-sized pan, heat the olive oil over medium-low heat. Add the thinly sliced red onion and cook for about 15-20 minutes, stirring occasionally, until softened and caramelized.
2. Add the balsamic vinegar, brown sugar, salt, and pepper to the caramelized onions. Stir well and cook for another 5 minutes, allowing the flavors to meld together. Remove from heat and set aside.
3. Lay out the slices of whole grain bread and spread a thin layer of butter on one side of each slice.
4. On the unbuttered side of four slices, evenly distribute half of the grated Gruyère cheese.
5. Spoon the caramelized onion mixture on top of the cheese, dividing it evenly among the four slices.
6. Next, add a layer of the slightly mashed blackberries on top of the caramelized onions.
7. Toast each side of the sandwich in a griddle pan until light golden brown and the cheese is melted.