Remove the steaks from the refrigerator 30 minutes before preparing the recipe.
Sprinkle ¼ teaspoon kosher salt evenly over both sides of each steak.
Add ¼ cup fresh cracked peppercorns to a plate and press each steak into the peppercorns, coating each side of the steak in pepper.
Place butter, olive oil and onions in a large cast iron skillet.
Preheat a grill over medium high heat (400-450°F).
Add the steaks to the grill, along with the cast iron skillet of butter, oil and onions.
Cook the steaks for 5 minutes per side.
Remove from the grill, place on a cutting board and cover with foil.
Let the steaks rest for 10 minutes.
In the meantime, add the mushrooms, garlic and Worcestershire sauce to the cast iron skillet on the grill, with the kosher salt and fresh cracked black pepper.
Cook for 5 minutes, stirring occasionally.
Reduce the heat on the grill to low, then pour in the heavy cream.
Stir constantly for 2 minutes, then remove the creamy mushroom sauce from the grill.
Plate the steaks, then top them with the mushroom cream sauce.
Notes
The steaks can be sliced before topping with the creamy mushroom sauce and serving, or they can be served unsliced and topped with the sauce. When slicing a New York Strip Steak, slice against the grain.
The steaks can also be cooked in a cast iron skillet on the stove over medium high heat, instead of on the grill. Make sure the skillet is hot before adding the steaks to the skillet. Cook for 5 minutes per side, or until the steaks reach your desired internal temperature.