A long with muscadine grapes, butter beans are among the farmer's market treasures of late summer in Charleston—reason to wake up with gusto to another day of stultifying heat and oxford-soaking humidity. We do all kinds of things with butter beans: we make a hummus-like spread for the cocktail hour, we simmer them with seasoning meats of all sorts, and we compose marinated salads aplenty. But this may be our most simple treatment yet, and one of the most satisfying.