Make the Blueberry Compote: In a medium saucepan, combine fresh blueberries, sugar, lemon juice, and lemon thyme. Cook over medium-high heat, stirring gently until it reaches a boil, then reduce heat to medium-low and let it simmer for 20 minutes.

Assemble Sandwiches: Take two slices of your favorite bread and spread a generous layer of cooled blueberry compote on one side of each slice. Sprinkle a mix of white cheddar and mozzarella over the compote, ensuring an even distribution. Top with the second slice of bread, compote side facing in.

Grill the Sandwiches: In a large skillet, melt a tablespoon of unsalted butter over medium heat. Carefully place your assembled sandwiches into the skillet. Cover with a lid and cook for 2–3 minutes or until the bread turns golden brown and crispy.

Flip and Finish Cooking: After the first side is golden, gently flip the sandwiches. Add another tablespoon of butter if necessary. Cover again and cook for an additional 2–3 minutes, ensuring the cheese melts beautifully.

Cut and Serve: Once grilled, remove sandwiches from the skillet. Cut each sandwich in half to reveal the melty cheese and vibrant compote inside. Optionally sprinkle with flaky sea salt and fresh thyme.