Mortadella Sandwich with Ricotta and Pistachio Pesto

• 1/2 cup packed fresh basil leaves
• 1/4 cup shelled pistachios
• 2 tablespoons extra-virgin olive oil

Salt and black pepper

• 6 (4 ½-inch) squares focaccia
• 1 1/4 pounds very thinly sliced mortadella
• 3/4 cup fresh ricotta
• 1 lemon

1. Finely chop the basil and pistachios together in a food processor or with a sharp knife. Transfer to a bowl, stir in the oil and season generously with salt and pepper.
2. If the focaccia isn’t freshly baked, toast lightly to warm but not crisp. Split each square in half through the fluffy middles.
3. Drape the mortadella over the bottom halves in wavy layered ribbons. Lightly spread the ricotta over the mortadella, then scatter over the pistachio pesto. Zest the lemon directly on top, then sandwich with the focaccia tops. Serve immediately.