Pat the steaks dry, and season with the steak seasonings of your choice.
Preheat a large stainless-steel skillet or cast-iron frying pan over medium heat.
Add the oil, and once it’s hot, add the steaks. The steaks should sizzle immediately when added to the pan.
Sear the steaks for approximately 3 to 4 minutes on one side and then flip over and cook for another 2 to 3 minutes (longer if you prefer your steak more well-done).
Remove the steaks from the pan to a large plate and let rest.
Add the beef stock and leeks to the pan, and scrape up all the browned bits from the bottom.
Reduce the heat to medium-low and simmer for 5 minutes.
Stir in the coconut milk, mushrooms, the mushroom soaking water, balsamic vinegar, salt and pepper.
Simmer over medium-low heat until the sauce has thickened somewhat, about 5 to 7 minutes.
Serve the creamy leeks and mushrooms over or alongside the steaks.