Perfect Boneless Beef Roasts - cooking recipe

Ingredients

4 lbs boneless beef roast, at least 2-1/2 to 3 inches thick, such as tenderloin, sirloin tip roast, eye of round roast, rib-eye (NO VERY TOUGH CUTS, PLEASE as cooking will NOT make them tender.)
seasoning or herbs
onion (optional)
mushroom (optional)
balsamic vinegar (optional)
beef broth (optional)
cornstarch (optional)

Preparation

NOTE: The success of this recipe will depend upon how accurate the temperature of your oven is and how will it retains heat. Adjust cooking time +/- according to your individual oven.
IMPORTANT: Determine the EXACT weight of the roast from the meat wrapper. Weight will determine how long to cook the roast. If you have a probe meat thermometer with an alarm, I recommend using it.
Preheat oven to 500 degrees.
Cut all visible fat from the outside of the meat. Rub the entire outside of the roast with salt, pepper, or seasonings of your choice, such as thyme, garlic powder, etc. (If using a probe thermometer insert it into center of the meat. Set the temperature to your desired degree of doneness and set the alarm.).
Place roast in roasting pan and bake according to the following Cooking Chart:
RARE - 3 minutes per pound.
MEDIUM RARE/RARE - 3 1/4 minutes per pound.
MEDIUM RARE - 3 1/2 minutes per pound.
MEDIUM - 4 minutes per pound.
MEDIUM WELL - 4 1/2 minutes per pound.
WELL DONE - not recommended with this method.
Set your oven timer for the cooking time calculated from the Cooking Chart above.
When cook time is completed, TURN THE OVEN OFF! DO NOT OPEN THE OVEN DOOR FOR AT LEAST 1-1/2 HOURS or until the probe alarm signals desired temperature has been reached. After removing roast from oven, tent with foil and let it rest for 5 minutes before slicing.
To reserve meat juices, slice rare/medium rare roasts on a platter where juices can collect. Pour juices into roasting pan, scraping loose any pan drippings, and pour au jus over the roast.
OPTIONAL ONIONS AND MUSHROOMS: Slice mushrooms and onions. In frying pan coated with non-stick cooking spray, saute mushrooms and onions until limp and tender. Add 2-3 tablespoons balsamic vinegar and set aside.
FOR GRAVY: For each cup of au jus (beef liquid), make a slurry by stirring 1-1/2 to 2 tsp of cornstarch into 1 tbs water. Bring au jus to a slow boil (adding 1 cup beef broth, cooked mushrooms and onions w/vinegar if using optional ingredients); stirring constantly. Gradually add the slurry to the boiling au jus. Cook on medium, stirring constantly, until mixture thickens - about 1 minute. Remove from heat and serve.