Take your favorite chocolate chip cookie recipe and add some extra melted butter to it, plus an extra egg yolk. The real trick is to follow the directions in The New Best Recipe book. Spoon up 1/4 c of dough and form it into a ball. Pull the ball apart to form two dough mounds with a jagged top. Rotate the mounds and push them back together with the jagged tops next to each other and facing upward. Place the dough balls on parchment-covered cookie sheets with the jagged edge up. You should end up with about 18 cookies, 9 on each sheet.
Bake them at 325 for about 18 minutes, rotating and swapping the sheets halfway through. Let them cool completely on the sheets before removing.