I used 2 Tbsp curry powder and 1.5 tsp cumin in place of the curry paste. It's important to have both cans of coconut milk to balance the liquid levels. If you don't have fish sauce, soy sauce is the next closest thing.
Getting the balance of sweet and sour depends on the lime juice, peanut butter, and brown sugar. Maybe omit the sugar if your PB is sweetened.
