Pulse 1 1/2 cups unsalted, shelled roasted natural pistachios, 1 cup chopped tomato, 2 garlic cloves, a handful of fresh mint leaves, a handful of grated Parmesan, a pinch of crushed red pepper flakes, and a pinch of freshly ground black pepper in a food processor until a coarse purée forms. Transfer to a bowl; stir in 2 Tbsp. olive oil (or more) to form a thick, chunky sauce. Season with kosher salt and pepper. Toss 1 cup pesto with 1 lb. freshly cooked pasta, adding pasta cooking liquid by the tablespoonful to form a glossy sauce.