Heat a grill pan over medium-low to medium heat until almost smoking. Lightly brush pan with olive oil. Place panino on pan; cover with a cast-iron or other heavy skillet weighted with soup cans. Gently press straight down. Grill, undisturbed, until browned and crisp on bottom, 3 to 4 minutes. With a spatula, flip panino. Repeat process; grill until crisp and browned on other side, 3 to 4 minutes more. Serve hot.
Panini are as quintessential an Italian experience as gliding through Venice in a gondola or tossing a coin into Rome's Trevi Fountain (which, legend has it, guarantees a return trip to the Eternal City). Panino (panini is the plural) literally means "little bread," and is Italian for sandwich. There, a good panino is made up of excellent bread, fresh or roasted vegetables, cheeses and meats, and, often, a drizzle of top-notch olive oil.
To gild the lily, Italians sometimes cook panini on a small electric grill -- panini alla piastra. The grill toasts the bread, imprinting it with an array of diagonal stripes. The pressure crisps the sandwich's surface as the bread stays dense and chewy; the flavors of the fillings, meanwhile, intensify and meld as they heat up.
Because panini are so delectable, so simple, and because they have European flair, they've become fashionable in the United States; affordable panini makers for the home are easy to find. But most Italians don't own one -- they use an ordinary grill pan. Heat the pan, pop the sandwich on, and compress it with another pan, weighted down, say, with soup cans. Distribute their weight to ensure the sandwich cooks evenly, and quickly wipe down the pan before making another. The process might seem a little fussy, but as soon as you bite into your panino, you'll be magically transported to Italy -- even if you've never thrown a coin into that famous fountain.