Nowadays, chocolate chip cookies sold in gourmet shops and cafés always come jumbo-sized (think saucer plate). These cookies are incredibly appealing and satisfying—thick and chewy rounds loaded with as many chocolate chips as they can hold. We wanted our own version that retained the soft and tender texture of these café cookies, even after a day or two (not that they’d be hanging around that long). One key element in achieving this cookie was melting the butter, which creates a product with a chewy texture. But to keep the cookie from becoming tough, we had to add a little extra fat, which we did in the form of an egg yolk; the added fat acts a tenderizer and prevents the cookies from hardening after several hours. MAKES 24 COOKIES To keep the cookies chewy longer, store them in an airtight container with a slice of sandwich bread.