Preheat oven to 400F. Move the racks so that the top one is in the center, and the bottom one is very close under it. You'll want to put a baking sheet covered with either a silicone sheet or foil to catch drips on the lower rack.
Mix flour, sugars, and salt in the crust with your finger. Yes, with your finger. That's not a typo.
Add the cream, and again, mix it into the ingredients with your finger. You'll be able to feel when everything is properly incorporated. You'll also be able to feel to make sure the crust has no holes or cracks in it.
Top off the pie with milk. There is no exact measurement for this, but you'll want to pour until the level of the milk comes just a little below where the pie crust is crimped. Don't mix the milk in... it'll mix while it bakes.
Dot the top of the pie with the butter cubes, then sprinkle cinnamon liberally over the entire top of the pie.
Bake at 400F for 15 minutes, then lower the temperature of the oven to 350F. Bake 45 minutes to an hour more. You'll know when it's done by watching the center of the pie. When it puffs up then falls back to the regular height again, it's done.
Cool completely before slicing.