"OMG, this recipe was exquisite! The only thing I changed was the wine, I used marsala instead of dry red as that's what I had open. The flavor was a perfect compliment to the beef. Other reviews said it was too bland but I wonder if they missed the recipe instructions to add salt after sauteing the onions, then season with S&P at the end. I did not use all of the butter (don't need the extra calories) and it was still delicious. You can easily make the sauce in advance and heat it up after the steak is grilled.