Cube the bread loaf into 1 inch cubes.
Add the cubed bread to a greased 9x13 casserole dish.
In a large bowl, whisk the eggs until smooth.
Add milk, cream, sugar, vanilla and cinnamon to eggs and whisk to combine.
Pour egg and milk mixture over bread cubes.
Gently push the bread down into the custard.
Cover tightly with plastic wrap or tight fitting lid and refrigerate for 8-10 hours or overnight.
In a medium bowl, combine the flour, brown sugar, cinnamon and salt.
Stir in the softened butter until everything is evenly incorporated.
Cover bowl and place in fridge with casserole.
Preheat oven to 350°.
Uncover casserole and sprinkle streusel topping evenly over the top.
Bake for 45-60 minutes. Bake less for a softer texter and longer for a firmer texture.
Let casserole rest for 10 minutes and the slice and serve with desired toppings.