In a karhai place the vegetable oil and bring to medium - high heat.
Add the curry paste and stir around until very aromatic. Next add the spinach and coriander for 30 Seconds until wilted. You can use Frozen spinach hear instead of fresh. Just ensure it's completely defrosted before continuing.
Put the chopped tomatoes into the Karhai and stir through, allow the curry to cook away at a medium simmer for 10 Minutes.
Just before you're ready to eat add the prawns and cook until completely hot or cooked through if you're using raw ones. Be sure not to overcook them as they will lose all of there wonderful flavour.