Paccheri and Cheese with Peas and Mint

INGREDIENTS

• 1/2 cup plus 2 tablespoons coarsely chopped fresh mint
• 1 cup shelled fresh or frozen peas
• Kosher salt and freshly ground black pepper
• 1 cup plus 2 tablespoons coarsely chopped flat-leaf parsley
• 2 cups coarsely chopped arugula
• 1 cup ricotta (about 9 ounces)
• 1/4 cup all-purpose flour
• 1 pound paccheri rigati or rigatoni
• 1/2 teaspoon finely grated lemon zest
• 1 cup shredded Fontina cheese
• 1/4 cup (1/2 stick) unsalted butter plus more for pan
• 4 cups whole milk
• 1 large egg
• 1/3 cup plus 1 1/2 cups grated Parmesan, divided (about 3 1/2 ounces total)