||Heat 10ml oil in large non stick pan over high heat. Cook beef in 2-3 batches for 5 minutes until well browned. Remove each batch as cooked.
||Reduce heat to medium. Add remaining oil, potatoes and onions to pan. Cook for 5-10 minutes until onion has softened and potatoes are browned. Add curry paste. Cook, stirring, for 5 minutes.
||Return beef to pan. Reduce heat to low. Add water and simmer uncovered for 20 minutes.
||Add coconut milk, sugar and fish sauce. Simmer, uncovered, for further 10 minutes until beef and potatoes are tender.
||Recipe Note: add 200g green beans during last 10 minutes of cooking if desired.