Ingredients:

2 tablespoons butter (preferably from grass-fed cows)
1 medium sweet onion, cut into quarters lengthwise, then sliced crosswise
1 small red bell pepper, cut into matchsticks
1 14 ounce can coconut milk (unsweetened), shaken well
1 1/2 tablespoons red curry paste (I make mine from The Spice House Thai Red Curry Powder, mixed with fish sauce to a paste)
1 tablespoon fish sauce (nam pla), if not used to prepare curry paste
3 tablespoons fresh lime juice
1-2 teaspoons coconut palm sugar, to taste (optional)
~ 2 or 3 tablespoons fresh cilantro, chopped
1/4 cup roasted cashews (optional)
1 to 1/2 pounds wild-caught cod fillets
kosher salt