Remove steaks from refrigerator and any packaging and let sit at room temperature for at least 30 minutes.
Combine the salt, peppers, onion powder, and garlic powder in a small bowl. Rub both sides of each steak with the rub mixture.
Preheat oven to 375 degrees. Preheat a heavy, oven-safe skillet over high heat until it is smoking hot. Add in 1 tablespoon canola oil and 1 tablespoon butter. Sear steaks in the hot pan for 2-3 minutes per side. Turn the steak onto its side and render the fat by searing it for 2-3 minutes as well. Remove steaks from pan and set aside briefly.
Add in remaining butter Add in mushrooms and and asparagus. Season both with salt and pepper and toss in the oil and butter over medium-high heat for 2 minutes. Scoot to the side and return the steaks to the pan.
Slide the skillet into the preheated oven to finish cooking, about 10-15 minutes for medium rare. Use a meat thermometer to ensure accuracy.