01 -
In a small saucepan over medium heat, combine blackberries, balsamic vinegar, honey, and a pinch of salt. Stir occasionally, mashing the berries to release juices, and cook until the mixture thickens and the fruit is broken down, about 5 minutes. Remove from heat and allow to cool slightly.
02 -
Generously spread softened butter on one side of each bread slice. Arrange two slices of bread, buttered side down, on a clean surface. Layer half of the brie cheese over each slice, spoon the cooled blackberry mixture evenly, and cover with the remaining brie slices. Top with the remaining bread, buttered side facing upwards.
03 -
Heat a non-stick skillet over medium-low heat. Place assembled sandwiches in the skillet and cook for 2 to 3 minutes per side, pressing gently with a spatula, until the bread is golden brown and the cheese is fully melted.
04 -
Transfer sandwiches to a cutting board, let cool for 1 minute, slice diagonally, and serve while warm.