1. Grease a 9x13 pan with butter. Tear bread into bite-size chunks and place evenly in the pan.
2. Mix together the eggs, milk, cream, sugar, and vanilla. Pour evenly over bread. Cover tightly and store in the fridge for several hours (I put mine in overnight....it was about 12 hours).
3. In a medium bowl mix together the flour, brown sugar, cinnamon, and salt. Cut in the butter with a pastry blender until it all looks nice and crumbly (like small pebbles, according to P-Dub). Place in a ziploc bag and put in fridge.
4. When ready to bake, take pan and bag out of fridge. Remove wrap and evenly sprinkle the crumb mixture over the top. Bake for 1 hour at 350 degrees (or 45 minutes if you like it more soft and pudding-like).