1
Heat the oil and add your garlic, chillies, ginger and curry leaves. Stir fry for a few minutes.

2
Chop the onions in a food processor (you’re looking for very finely chopped rather than puréed) and add to the oil. Cook for 5 minutes until lightly browned, making sure it doesn't stick or burn.

3
Stir in the curry powder and whiz the tin of tomatoes in your food processor. Add the tomatoes and cook for another 5 minutes. Your curry sauce is now ready.

4
To complete the dish, brown some meat (chicken, lamb, etc.) or vegetables (parsnip, okra, mushrooms, whatever takes your fancy) and add to the sauce. You could also use a thick white fish fillet (haddock, cod, coley, conger, etc.). Simmer covered for a further 10 minutes (30 minutes for lamb) and finish off by stirring in the chopped coriander and garam masala.