Peel onion and ginger and chop both finely. Heat the oil in a pot. Fry onion and ginger for about 2 minutes. Stir in tomato paste and curry and sweat for about 1 minute. Deglaze with orange juice and coconut milk.
Bring to the boil and simmer for about 5 minutes. Stir starch and 3 tbsp. water until smooth. Stir into the boiling coconut sauce, continue to simmer for about 1 minute while stirring. Season to taste with salt and pepper. Best served warm.