- 1/2 pound thinly sliced pancetta
- 1 pound ground pork
- 1/2 pound ground veal
- 1/2 pound ground beef chuck
- Kosher salt
- 1/2 teaspoon ground cinnamon
- 1/2 teaspoon ground allspice
- 1/4 teaspoon ground cloves
- 1/4 teaspoon freshly grated nutmeg
- Two large bunches of broccoli rabe (about 2 1/2-pounds), large stems trimmed
- 2 tablespoons extra-virgin olive oil
- 2 medium garlic cloves, minced
- 3/4 teaspoon crushed red pepper
- Freshly ground pepper
- 6 ounces Italian Fontina cheese, cut into 6 slices
- 6 kaiser rolls, split and lightly toasted
- Lay the pancetta on a baking sheet lined with plastic wrap and freeze until firm. Finely chop the pancetta, then transfer it to a food processor and pulse until minced.
- In a large bowl, combine the ground pork, veal and beef with the minced pancetta. In a small bowl, combine 1 teaspoon of salt with the cinnamon, allspice, cloves and nutmeg. Sprinkle the spices over the meat and mix thoroughly but gently with your hands. Pat the meat into 6 burgers and refrigerate.
- Light a grill. In a large pot of boiling salted water, cook the broccoli rabe until just tender, about 2 minutes. Drain, lightly squeeze out any excess water and coarsely chop.
- Heat the olive oil in a large skillet. Add the garlic and crushed red pepper and cook over moderate heat until fragrant, about 1 minute. Add the broccoli rabe and cook, stirring, until heated through. Season with salt and pepper.
- Season the burgers with pepper and grill over a hot fire until just cooked through, about 5 minutes per side. Melt the Fontina on the burgers about 1 minute before they are done. Spoon the broccoli rabe onto the bottom buns, then set the burgers on top. Close the sandwiches and serve at once.
The uncooked burgers can be refrigerated overnight.