- 4 medium baking potatoes
- 12 cloves garlic, smashed -- roughly chopped
- 1 cup olive oil
- 2 teaspoons kosher salt
- Freshly ground black pepper -- to taste
- 4 portobello mushrooms -- 3/4-1 lb total
- stem ends trimmed and caps wiped clean
- 2 pounds flank steak -- trimmed of fat
Place one oven rack on lowest level and one rack on the next level above. Heat oven to 500°.
Forty minutes before roasting the steak and mushrooms, use a fork to prick the potatoes once or twice each. Place them directly on the sides of the upper rack of the oven, allowing enough room for the mushrooms, which will cook on the same rack.
Put the garlic in the blender or food processor with 4 tablespoons of the oil. Blend until smooth. Scrape down sides with a rubber spatula. Add remaining oil and salt and pepper. Blend until smooth.
Put the mushrooms in a 12-by-8-by-1 1/2-inch roasting pan.
Using the spatula, scrape out half of the garlic mixture into the pan. Rub the puree into both sides of each mushroom cap. Allow to marinate for at least 30 minutes. Put steak in shallow container large enough to hold it. Pour over remaining garlic mixture and rub into both sides of steak. Let marinate on kitchen counter at least 30 minutes or until meat comes to room temperature.
Before roasting the steak and mushrooms, put a 14-by-12-by-2-inch roasting pan on the lower oven rack and preheat for 10 minutes. Remove pan.
Immediately, put the steak with all of its marinade in the pan. Place on the lower oven rack, the thickest p art of the steak to the rear of the oven. Place the mushrooms on the upper rack at the same time.
For rare, roast the steak on one side for 6 minutes (for medium, 8 minutes).
Turn the steak and the mushrooms. Roast 6 minutes more. Remove steak, mushr ooms and potatoes from oven. Let steak rest about 5 minutes. Slice thinly against the grain at a 70-degree angle.Makes 4 servings.