Infallible Rare Roast Beef (This really works!)

1 roast beef, with or without bones, ANY SIZE

In the morning, preheat oven to 375F. Put roast in and cook for 1 hour. Turn off heat. Leave roast in oven. Do not open door. Thirty minutes before serving, turn oven back on to 375F. If you need the oven for something else, take it out to "rest" and cover with aluminum foil. Every slice is uniformly pink and gorgeous. The first few times you do this takes courage!

From Barbara Blaxter in 3 Rivers Cookbook III