The grilled sandwiches that we know today as panini are believed to have originated in the mid-20th century in Italy’s paninoteche (sandwich shops). Whatever their history, panini offer a tantalizing combination of warm, toasted bread, salty meats and melty cheese. Our panini also include sautéed broccoli rabe, which offers a bitterness to offset the richness of mortadella and provolone while also making these simple sandwiches complete meals. We spread vinegary crushed red peppers on the bread to add piquancy—sometimes labeled as “hoagie spread,” it’s sold jarred in most supermarkets. Chopped peperoncini or cherry peppers would be a good substitute.