In a small saucepan, combine 1 cup of fresh or frozen blueberries with 2 tablespoons of sugar. Cook over medium heat for about 5–7 minutes, stirring often until the blueberries break down and achieve a jammy consistency.

Spread a generous layer of cream cheese or brie on one side of each slice of sourdough or white bread. Add a layer of melted mozzarella or fontina cheese on top of the cream cheese, and spoon the blueberry mixture evenly over the cheese. Place the remaining bread slices on top, cream side down.

Heat a skillet over medium-low heat. Spread 1.5 tablespoons of butter on the outer sides of each assembled sandwich.

Once the skillet is warm, place the sandwiches in the pan. Cook for about 3–4 minutes per side, pressing down gently with a spatula.

After cooking both sides to perfection, remove the sandwiches from the skillet and let them rest for 1–2 minutes.

Plate your Blueberry Grilled Cheese sandwiches and serve warm.