Macadamia nuts bring richness and body to this flavorful coconut-based sauce; they're readily available stand-ins for the candlenuts commonly used in Southeast Asian cooking. If you can only find raw macadamia nuts, roast and cool them before adding to the blender. You can buy peeled shrimp, but make sure they have the tails attached; the tails are used to infuse the sauce. We preferred unrefined coconut oil for this dish because of its pronounced coconut flavor, but refined coconut oil worked well, too. Fresno chilies are fresh red chilies with mild heat; if you can't find them, substitute fresh cherry peppers.