Preheat your oven to 350°F (175°C) and lightly grease a 9x13-inch baking dish.
In a large bowl, whisk together the eggs, whole milk, heavy cream, brown sugar, vanilla extract, ground cinnamon, nutmeg, and salt until fully combined.
In another bowl, toss the diced apples with lemon juice to prevent browning.
Add the cubed brioche bread and diced apples to the egg mixture, folding gently until the bread is well coated and the apples are evenly distributed. If using, fold in the chopped pecans for added crunch.
Pour the mixture into the greased baking dish, spreading it out evenly.
Cover the dish with aluminum foil and bake in the preheated oven for 30 minutes.
After 30 minutes, remove the foil and bake for an additional 15-20 minutes, or until the top is golden brown and the casserole is set.
Once baked, let it cool for a few minutes before slicing.
Dust with powdered sugar before serving and drizzle with maple syrup for an extra treat.
Notes
Serve warm with powdered sugar and maple syrup for an extra treat.