Place your melted butter in a 8x8 casserole dish, make sure it coats all sides and bottom.
In a separate bowl, mix your eggs, milk, ½ cup brown sugar, vanilla, cinnamon, and nutmeg. Add your bread cubes and toss together lightly. Dump your mixture into the casserole dish.
Sprinkle the remaining 1/4 cup brown sugar all over the top of your mixture. This will give it a nice, caramel-ish crust.
Top with your chocolate sauce and enjoy.