how do I cook a 1 and a half pound tri-tip in the oven for it to be very tender and medium rare?

Answer 1

Oven Roasted Tri-Tip

1 teaspoon salt
1/2 teaspoon freshly ground black pepper
1 tablespoon finely chopped garlic
Dry rub or marinade of your choice.
1 1/2 to 2 1/2 pound beef tri-tip, fat trimmed to 1/4 inch
Pan Sauce: (do not make if you use a wet marinade)
1/2 cup beef or chicken stock
1/4 cup red wine
1 teaspoon chopped fresh herb of your choice such as thyme or rosemary, or 1/2 teaspoon dried
1 tablespoon Dijon mustard
Salt and freshly ground black pepper
Flavor Step: If you're using the garlic rub or a dry rub, combine all ingredients and generously season or rub the meat all over and let it stand at room temperature for up to 2 hours. Or cover the roast and leave it overnight in the refrigerator; let it sit at room temperature for 2 hours before cooking. If you're using a wet marinade, puncture the meat all over with a meat fork or skewer. Place it in a zip-lock bag or large bowl and pour the marinade over the meat. Marinate (cover if using a bowl), for up to 2 hours at room temperature or overnight in the refrigerator. If the meat has been refrigerated, let it sit at room temperature for 2 hours before cooking.

Preheat the oven to 450ƒF. Remove the meat from the marinade and pat it dry. Discard the marinade. Place the tri-tip, fat side up, on a rack in a shallow roasting pan. Roast for 20 minutes, then begin checking the internal temperature: You should remove the roast at 115ƒF to 120ƒF for rare, 120ƒF to 125ƒF for medium-rare.

Transfer the meat to a carving board or platter, cover loosely with foil, and let it rest for 10 to 15 minutes before carving to allow the residual heat to complete the cooking and the juices to stabilize.

Meanwhile, make the optional pan sauce: Pour off any fat from the roasting pan. Place the pan over a burner and add the stock, wine, and herbs. Bring to a boil, scraping up any browned bits from the bottom of the pan. Reduce the sauce almost to a syrup. Whisk in the mustard and taste for salt and pepper.

Slice the meat into thin slices across the grain. If you made the sauce, pour it over the sliced meat, and serve.

Answer 2

You should cook it slow, and at a low heat. To seal in the juices you might try searing it in a pan first to brown the outside of the meat on all sides and to keep it from drying out, never use salt on beef while cooking, always add salt after.