In a frying pan, heat 1 tablespoon oil on fairly high heat, brown the minced beef, breaking it up as it cooks. When cooked, drain and rinse in hot water. Leave in colander.
Wipe frying pan and add 2 tablespoons oil. Over medium heat, saute onion until translucent. Add the garlic and gently fry for 1 minute. Do not brown garlic as this makes it bitter. Add the curry powders. Stir and cook until aromatic. Add a little more oil if needed.
Add the coconut milk and stock, bring to boil. Add the Thai green curry paste. Stir until well combined. Add the fish sauce, salt, pepper, sugar and cooked minced beef. Stir well. Bring to a boil. Turn heat down, cover and simmer 20 minutes.
Add cubed potato to curry 8-10 minutes before end of cooking time (optional). Serve with basmati rice.
Made this as written with the addition of kumera at potatoe stage and coconut cream instead of milk. Got mmmm 's from the crew and leftover snatched up in lunch boxes. Would do it again!! - 02 May 2016