Divide the blueberry jam between 4 slices of bread and top each slice with 2 basil leaves. Divide the brie and goat cheese between the other 4 slices of bread. Combine the blueberry jam and cheese slices of bread to create a sandwich. Slather the outside of both sides of the sandwich in butter and sprinkle with garlic salt.
Heat about a tablespoon of olive oil in a large cast iron skillet over medium to medium low heat (the pan should be hot to properly heat the oil but not smoking). Add the sandwiches and toast for 3-4 minutes per side, or until golden brown and crispy. Remove the sandwiches from the pan and transfer to baking sheet.
**These sandwiches pair perfectly with a drizzle of balsamic glaze or honey.