Grease a 9 x 13 baking dish. Set aside.
Spread bread cubes evenly in the prepared baking dish.
In a large bowl, whisk together the eggs, milk, heavy cream, brown sugar, sugar, vanilla, cinnamon and salt.
Pour the mixture over the bread pieces in the prepared baking dish. Cover tightly
with plastic wrap and store in the refrigerator for several hours or overnight.
In a small bowl add butter, brown sugar, flour, cinnamon, nutmeg, and salt.
Use a fork or your hands and mix the ingredients to combine until the mixture resembles coarse crumbs.
When ready to bake preheat the oven to 350 degrees.
Remove the French Toast from the oven and sprinkle with the streusel topping.
Bake for 40-45 minutes or until the French toast is golden brown.
Serve warm with butter and syrup.