Prepare steak by removing from refrigerator 30 minutes before cooking.
Coat with olive oil, salt and pepper liberally. This can be done the day before.
Lay Hanger steak over direct heat for approximately 5-6 minutes and then flip over using tongs. Cook other side for another 5-6 minutes until the internal temperature of the meat is around 122-126 degrees F (for medium rare). Size and thickness of steak may adjust cooking time. If flare ups, move the meat to indirect side and close lid to cook.
Remove from grill and let sit for 10 minutes to let the juices settle and then cut against the grain.
Pour sauce over steak for flavor.
To make the Red Wine Reduction Sauce
Add olive oil to medium saucepan over medium heat and add shallots, cook for up to 5 minutes. We wanted to soften, not caramelize. Then bring the remainder of reduction sauce ingredients (EXCEPT butter) to a boil in a small saucepan, and then reduce to a simmer. Let reduce to half (approx 10 minutes) and remove from heat.
Immediately finish the sauce with butter, stirring, and when melted, strain to remove the shallot and rosemary pieces. The sauce will continue to thicken as it cools. Serve over slices of the hanger steak.