It's worth taking a stroll through Frascati's lively old center. Via Battisti, leading from the Belvedere, takes you into Piazza San Pietro with its imposing gray-and-white cathedral. Inside is the cenotaph of Prince Charles Edward, last of the Scottish Stuart dynasty, who tried unsuccessfully to regain the British Crown, and died an exile in Rome in 1788. A little arcade beside the monumental fountain at the back of the piazza leads into Market Square, where the smell of fresh baking will entice you into the Purificato family bakery to see the traditional pupi biscuits, modeled on old pagan fertility symbols.
Take your pick from the cafés and trattorias fronting the central Piazzale Marconi, or do as the locals do: buy fruit from the market gallery at Piazza del Mercato, then get a huge slice of porchetta from one of the stalls, a hunk of casareccio bread, and a few ciambelline frascatane (ring-shape cookies made with wine), and take your picnic to any one of the nearby cantine (homey wine bars), and settle in for some sips of tasty, inexpensive vino.