Preheat oven to 400 degrees. Line a section of a shallow baking sheet with aluminum foil, turning up the sides to make an edge. Lay bacon slices on foil without overlapping. Place grapes on unlined section of sheet and drizzle with oil. Bake for 15 minutes or until bacon is browned and grapes begin to burst. Drain bacon on paper towels.

Layer bread slices with brie cheese, roasted grapes and bacon slices. Melt butter in a skillet. Pan fry sandwich on both sides until golden brown and cheese has melted.