Heat the olive oil in a small frying pan over a medium heat. Add the onions and fry for 2-3 minutes, until softened.
Place the coriander seeds, cumin seeds, chilli flakes and ginger into a pestle and mortar and grind to a powder.
Add the ground spices and chilli flakes and tomatoes to the onions and simmer gently over a low heat for 10 minutes, or until the tomato has softened and become a sauce.
To serve, pour into a bowl and leave to cool.
