Trim and discard rind from Brie round. Cut Brie into 1/4-inch-thick slices. Cut apple into slices. Layer 4 Italian bread slices with Brie, apple slices, arugula, and turkey. Top each with 1 bread slice spread with 1 Tbsp. Bacon Marmalade. Brush sandwiches with melted butter. Cook sandwiches, in batches, in a preheated panini press 3 to 4 minutes or until golden brown and cheese is melted. Serve immediately.