Whisk together in a baking dish or bowl that’s large enough to hold your meat or fish: 3-4 large spoons extra virgin olive oil; 1 spoon Dijon mustard; juice of ½ lemon; 1 clove minced garlic; pinch of kosher salt and black pepper. For chicken, we like to add some chopped rosemary or thyme; for fish, thyme or dill will work very nicely. A dollop of soy sauce is also a good addition for fish if you want to add that flavor, but go easy on the salt because even lower sodium soy sauce has a fair amount of salt in it.