Heat oil in a non stick wok over a high heat. Cook beef (in batches if need be) for 3-4 minutes until browned on all sides. Remove from wok.
Reduce heat to medium and add onion and potato to wok. Cover and cook for 5 minutes to soften without browning too much.
Add Five Tastes Curry Paste, cook for 1 minute or until fragrant. Stir in coconut milk and fish sauce, simmer for 5 minutes or until potato is tender.
Return beef to wok, add peanuts and bring back to the boil. Serve garnished with coriander.