Chopped plum tomatoes, 2.5kg
Onion, chopped, 1
Wine or cider apple vinegar, 300ml
Ground ginger (preferably fresh), 100g
Garlic cloves, crushed, 12
Dried chilli, 1t
Tamarind paste, 2T
Sugar, 150g
Salt, 4t
Fry onion until soft.
Add all other ingredients and simmer for an hour.
Blend (preferably when cool for safety).
Keeps for weeks (if not months in the fridge).
Can be frozen in plastic sqeeze bottles.
Source
Based on recipe from Roden p 209.