Begin by greasing the baking dish with butter to prevent sticking.
In a large bowl, whisk together the eggs, milk, heavy cream, granulated sugar, vanilla extract, ground cinnamon, and salt until well combined.
In a separate bowl, toss the diced apples with brown sugar and lemon juice to coat them evenly.
Layer half of the bread cubes in the greased baking dish. Spread half of the apple mixture over the bread, followed by the remaining bread cubes and then the remaining apples.
Pour the egg mixture evenly over the layered bread and apples, pressing down slightly to ensure all bread is soaked. Cover with aluminum foil and refrigerate overnight (or at least for 4 hours).
Preheat your oven to 350°F (175°C) when ready to bake. Remove the foil and bake for 30-35 minutes until the top is golden and the center is set.
Serve warm, drizzled with maple syrup or additional powdered sugar, if desired.