Grease a 9x13 baking dish with avocado oil spray
Cut brioche bread into 1-inch cubes and add in an even layer to the baking dish
In a large bowl, whisk together eggs, milk, heavy cream, brown sugar, vanilla extract, cinnamon, nutmeg, and salt
Pour the egg mixture evenly over the bread and gently press down so the bread soaks up the custard
Let sit for at least 30 minutes so the bread absorbs the mixture
Bake at 350°F for 40-50 minutes until golden brown and set in the center
Cool slightly before serving
Serve warm with maple syrup, powdered sugar, or fresh berries
