1. Melt 4 tablespoons butter in a large saucepan over medium-low heat. Add apples, lemon juice, vanilla bean and scrapings, sugar, and brandy or Calvados, if desired. Cook until apples break down and become a chunky applesauce, about 20 minutes. Continue cooking over low heat until mixture is stiff enough to hold its shape when you press a spoon into it, 10 to 15 minutes longer. Remove and discard vanilla bean. Let sauce cool, and refrigerate until cold.

2. Heat oven to 400 degrees. Trim crusts from bread, and discard. Place 4 slices of bread together in a square, and place a 7-inch charlotte mold on top. Trace shape of mold onto bread with knife tip, and cut bread to fit in bottom of mold. Butter both sides, and fit into mold.

3. Reserve at least 4 slices of bread for the top; cut remaining slices in half lengthwise. They should be about the same height as the mold. Butter rectangles on both sides, and fit them against walls of mold, overlapping like shingles. Fill with apple mixture. Cut reserved bread to fit top of mold; butter, and fit into place. Chill 15 minutes.

4. Bake until bread is golden brown, 30 to 40 minutes. Let cool in pan for at least 30 minutes. Unmold, and serve warm, with whipped cream, if desired.