Stir all ingredients except for peanuts over medium heat until well combined. Note that if you are using natural peanut butter, you may more fish fish sauce and sugar since natural peanut butter does not contain additional salt and sugar. Start with 1 tbsp of each an adjust as needed.
Taste to make sure flavors are balanced. Add more fish sauce, sugar, vinegar or curry paste as needed.
If peanut sauce is too thick, add more coconut milk.
Transfer to serving dish and top with crushed peanuts for garnish.
