In a large skillet, saute beef in 1 tablespoon oil until no longer pink. Remove from skillet and set aside.
Spoon 1/2 cup cream from top of coconut milk and place in the pan. Add remaining oil; bring to a boil. Add curry paste; cook and stir for 5 minutes or until oil separates from coconut milk mixture.
Stir in the brown sugar, fish sauce and remaining coconut milk. Bring to a boil. Reduce heat; simmer, uncovered, for 5 minutes or until slightly thickened. Add bok choy and red pepper; return to a boil. Cook and stir 2-3 minutes longer or until vegetables are tender.
Stir in the cashews, cilantro and beef; heat through. Serve with rice.
Editor's Note: This recipe was tested with regular (full-fat) coconut milk. Light coconut milk contains less fat.