This sauce brings Mediterranean savor to summer grilled fish. My preferred fish for summer grilling is a good-sized porgy, which is a medium-fatty, firm-fleshed white fish with a mild flavor and edible skin. (The fish are called scup in Massachusetts and parts of New England; in other parts of the country, similar fish may be called sea bream, sheepshead or grunt.) But this sauce is perfect as a condiment with just about any grilled fish. You could also use it on seafood, meat or vegetables. If you prefer a more robust garlicky flavor, feel free to add more garlic to taste.