In Sicily and Calabria, Italy, a lemony, rustic sauce called salmoriglio is very popular, and when used as a steak marinade, it can turn even a cheap cut of meat into a gourmet dinner.
Salmoriglio is made by whisking together olive oil, oregano (fresh or dried), and salt with water and lemon juice. You can nix the water for a more intense lemony flavor.
A standard formula for Salmoriglio uses a 1/4 cup of lemon juice for every 1/2 cup of olive oil. The water can be equal to the lemon juice, but use less if the sauce is too thin.
For each 1/2 cup of oil, you can use 2 tablespoons of fresh oregano or 2 teaspoons of dried. Add a minced clove of garlic or two before salting the whole thing to taste.
The finished sauce is normally paired with seafood, but its punchy acidity makes it great company for steak as either a marinade or a sauce on top.
Salmoriglio can tenderize tough cuts while adding plenty of flavor, but don't let the meat sit longer than six hours, as the acidic ingredients will eventually make it mushy.
Salmoriglio adds complexity and brightness to meaty and rich steak, striking a nice balance of lemony, herbal notes that still let the meat's flavor shine.