Not a marinade, but very nice preparation:
Rub both surfaces of the steak with a mixture of salt, paprika and black pepper (the more the merrier).
When both sides are coated, fry both sides in a pan until it is quite brown. Then pour boiling water into the pan and put a lid on the pan. Keep checking the water level has not dried out, and cook the steaks or any sort of meat for about an hour with the lid on. The water makes a self-gravy. It is a delicious way to tenderise the meat.