Place the cubed bread evenly in a greased casserole dish.
Whisk together the eggs, dairy-free milk, melted dairy-free butter, brown sugar, vanilla extract, cinnamon, nutmeg, and a pinch of salt in a large bowl.
Pour the egg mixture evenly over the cubed bread in the casserole dish. Use a spatula or your hands to gently press down the bread, ensuring it's soaked in the mixture.
Cover and refrigerate at least 1 hour (or overnight for a more intense flavor).
Mix the melted dairy-free butter, brown sugar, cinnamon, and chopped nuts in a small bowl. Sprinkle evenly over the casserole.
Preheat the oven to 350°F (175°C) and bake for 35-40 minutes, or until the top is golden brown and the casserole is set. If you prefer a softer texture, bake for a shorter time; for a crispier top, bake a little longer.
Let it cool for a few minutes, then serve warm with a drizzle of maple syrup or a dusting of powdered sugar!