Sometimes the easiest way to cook something is also the best. From the hundreds of effortless dishes published in Gourmet over the years, the editors selected the best loved, the most memorably simple, and the riotously tasty--the ones that have entered their personal repertoires. They include vegetarian mains like Black Bean Burgers; seafood dishes that are ready in minutes, such as Seared Scallops with Tarragon-Butter Sauce; quick-cooking favorites like Deviled Chicken Drumsticks; andfor dessert, Chocolate Fallen Soufflé Cake.    All of the recipes come with cooking times, and menus are included.