Grease a 9x13-inch baking dish with butter or non-stick spray.
Add the cubed bread, apples, and nuts (if using) to the dish. Toss to combine.
1 loaf store-bought cinnamon swirl bread, 2 medium apples, ½ cup chopped pecans
In a blender or mixing bowl, combine the eggs, milk, cream, sugars, butter, cinnamon, vanilla, and nutmeg until smooth. Be careful not to over-blend if using a blender.
4 large eggs, 2 cups whole milk, 1 cup heavy cream, ½ cup granulated sugar, ¼ cup light brown sugar, 1 teaspoon ground cinnamon, 1 teaspoon vanilla extract, ¼ teaspoon ground nutmeg, ¼ cup unsalted butter
Pour the custard mixture over the bread and apples. Press the bread down gently to help it absorb the custard.
Cover with plastic wrap, and refrigerate for at least 30 minutes.
When ready to bake, preheat your oven to 350°F (175°C).
Remove the plastic wrap, cover with foil, and bake for about 25-30 minutes. Remove the foil and continue baking for another 14-17 minutes until golden brown and set. A butter knife should come out clean when inserted in the center.