In a medium saucepan, combine fresh blueberries, sugar, lemon juice, and finely chopped fresh thyme. Bring the mixture to a boil over medium heat, then reduce to medium-low and let it simmer for about 15-20 minutes, stirring occasionally until thickened.

Take two slices of your chosen bread and spread the blueberry compote on one side of each slice.

Layer about a quarter cup each of shredded white cheddar and mozzarella cheese over the blueberry compote on one slice of bread. Place the second slice on top, compote side down.

Heat a skillet over medium heat with a pat of unsalted butter. Once melted, place the sandwich in the skillet. Grill for approximately 2-3 minutes on each side.

Once golden and crispy, remove the sandwich from the skillet, allow to cool slightly, slice in half, sprinkle with flaky sea salt, and garnish with fresh thyme.