- 1 stick (8 tablespoons) butter,
- 2 pounds crisp, firm apples, such as Granny Smith, cored, peeled and sliced ¼-inch thick
- 6 tablespoons granulated sugar
- Pinch salt
- 12 slices good quality white loaf bread, 6 slices left whole, 3¼- to 3 1 /2-inch circles cut from remaining 6 slices.
- Heat 2 tablespoons of the butter in a large skillet over medium-high heat. Add apples, sugar, and salt; cover and cook until apples are just soft, about 5 minutes. Uncover and continue to cook until apple juices have reduced to a thin syrup, a couple of minutes longer. Transfer apples on a rimmed baking sheet; set aside.
- Rinse and dry skillet; return to medium heat. Working in 3 batches, heat another 2 tablespoons of butter until golden-brown; add 3 bread slices and sauté on one side only until golden brown, 1 to 2 minutes. Repeat with remaining butter, 3 bread slices and finally bread circles, also toasting only on one side.
- Adjust oven rack to lower-middle position and heat oven to 375 degrees. Using a smaller 2½-inch cookie cutter cut a circle in the center of each of the 6 whole bread slices. Place each circle, toasted side down, in the bottom of each of 6 custard cups. Arrange remaining bread scraps, toasted side out to fill in cup sides (overlapping is OK). Spoon a portion of apple filling into each cup. Top each with a toasted circle, toasted side up. Place custard cups on a rimmed baking sheet; bake until tops are crisp and charlottes are warmed through, about 15 to 20 minutes. Cool slightly, then invert to unmold. Charlottes can be made a couple hours ahead and reheated in a 300-degree oven until warm and crisp.
Using rectangular-shaped bread (about 4- by 5-inch slices), you should only needed 1 slice for the custard cup bottom and sides.