Begin by rinsing 1 cup of fresh blackberries under cool water and gently patting them dry with a paper towel. Place the blackberries in a small bowl and drizzle with 1 tablespoon of balsamic vinegar. Let marinate for about 5 minutes.

Preheat a skillet over medium-low heat. Once heated, add 1 to 2 tablespoons of butter, swirling it around as it melts.

Spread a generous layer of creamy brie cheese on one side of each of the 2 slices of artisanal bread. Place the marinated blackberries evenly over the brie on one slice.

Top with the second slice of bread, brie side down, to create a sandwich.

Place the sandwich in the skillet and grill for about 3 to 4 minutes until the bottom is golden brown and the brie begins to melt. Press down lightly on the sandwich to help with melting.

Flip the sandwich and grill the other side for another 3 to 4 minutes until golden brown and the brie melts beautifully.

Remove the sandwich from the skillet and let it rest for 1 minute. Slice in half and serve warm.