In a medium saucepan over medium heat, melt 2 tablespoons of the butter. Add the mushrooms slices and sauté until golden brown, about 4 minutes.
Add the garlic and sprinkle with salt and pepper, and cook one minute more. Remove and let cool, then use a fork to mix the mushrooms into the remaining butter. Place the butter on a piece of waxed paper and wrap it up, then roll into a log. Refrigerate until firm.
Allow the steaks to come to room temperature for at least 30 minutes before cooking. Season the steaks on both sides with salt and pepper.
Heat a large skillet over medium high heat. Once hot, add the oil and let heat for about 1 minutes. Add the steaks and sear 3 to 5 minutes per side, depending on thickness. Remove from heat and let rest in the pan another 3 minutes or so, until the internal temperature reaches 140F to 150F.
Serve with a large dollop of Mushroom Garlic Compound Butter on top.