Dessert for lunch? Yes, please! You are going to love this sweet and savory combo.
Spread 1/2 tablespoon of the caramel sauce on 1 side of each bread slice.
Trim and discard rind from Brie; thinly slice trimmed Brie. Top 4 of the bread slices evenly with sliced Brie. Top Brie evenly with thinly sliced apple (4 to 5 slices on each). Place remaining 4 bread slices, caramel side down, on top of apple slices.
Melt 2 tablespoons of the butter in a griddle or large skillet over medium. Cook 2 sandwiches at a time in preheated griddle, until golden brown and cheese is melted, 3 to 4 minutes per side. Repeat with remaining butter and 2 sandwiches. Dust each with powdered sugar, and serve with caramel sauce for dipping.