Step 1: To make the pesto, bring a small pot of water to a boil. Prepare an ice bath. When the water is boiling, blanch the basil leaves for 10 seconds, then transfer them to the ice bath using a large fine mesh sieve. Remove the basil from the ice bath and squeeze out as much moisture as you can. Finely chop. While this step might feel unnecessary, it helps to preserve the basil’s fresh green color in the final product. 

Step 2: Add the pistachios to a food processor and pulse until they resemble small pebbles. Add the basil, and with the motor running on low drizzle in the olive oil until the mixture just comes together - we’re looking for a rustic texture, not a fully homogeneous sauce. Fold in the parmesan, and season with black pepper and a pinch of salt to taste. 

Step 3: To make the grilled cheese, begin by heating a cast iron pan over medium heat. Drizzle one side of both pieces of bread in oil, and place the slices oil side down in the hot skillet. Toast until golden, 3-4 minutes. Remove the skillet from the heat while you build the sandwich. 

Step 4: Slather both sides of the toasted bread generously in pesto (about 2 tablespoons per side). Cover the surface area of both pieces with torn mozzarella, then carefully top one side with the flaked smoked salmon. Season with lemon zest and fresh cracked black pepper, then close the sandwich by folding over the other piece of bread. 

Step 5: Place the skillet back over medium-low heat, and add a small glug of olive oil. Place the sandwich in the skillet. Drizzle another bit of olive oil on the bare, top piece of bread. Cook for about 5 minutes on each side, until the bread is golden and the cheese has fully melted. If your bread is taking on too much color before the cheese has properly melted, lower the heat and cover the pan with a lid to trap in enough steam to help nudge the process along. 

Step 6: Cut in half and enjoy warm.