Angus Rib Steaks Napped with Oyster Mushroom Sauce

Mushrooms
Preheat the oven to 400°F (200°C).
In a frying pan, sear the mushrooms in the oil over medium heat for about 3 minutes.
Sprinkle rosemary over the mushrooms.
In an oven-proof dish, place the mushrooms and set aside.
Heat a heavy-bottomed pan over medium-high heat until very hot, but not smoking. Coat the bottom with oil and butter.
Sear the steaks until nicely browned, about 3 minutes per side.
Place the steaks on the mushrooms.
Broil uncovered in the oven for 5 to 7 minutes.
Meanwhile, over medium-high, heat the frying pan used to cook the mushrooms.
Pour in the wine and balsamic vinegar. Bring to a boil and deglaze the bottom of the pan. Add the broth and tomato paste; boil for about 5 minutes (or until the liquid becomes a little syrupy).
Remove from the heat and whisk in the butter. Fold in the mushrooms.
Place the steaks on dinner plates and nap with the oyster sauce.