Grease a 9×13" baking dish. Cut bread into 1 inch chunks and place in pan.

Assemble: Whisk eggs in a large mixing bowl. Add cream, milk, brown sugar, cinnamon, salt and vanilla and mix well. Pour evenly over the bread cubes and toss gently to combine. Spread into an even layer in the pan. Refrigerate overnight.

Topping: Add brown sugar, white sugar, cinnamon and nutmeg to a bowl and stir to combine. Add butter and use a pastry blender or your hands to combine until crumbly. Cover and refrigerate until morning.

Bake: Preheat oven to 350 degrees F (180 degrees C). Uncover french toast pan and sprinkle the topping evenly over top. Bake for 45-50 minutes or until top is golden and casserole is set.

Allow french toast to cool for at least 10 minutes before serving. Top with homemade syrup, berries, whipped cream, or any other toppings you'd like.