Yes, I thought about food colouring... but it's not quite
that bright and red.
Actually last night's (Thursday's) curry was the best using this base so far, and I managed to get the colour more reddy-golden. The only differences to the last version I posted were:
After the chopped onion and pepper were flashed off, I added one very heaped tsp of tomato puree and stir fried it untill it had completely broken up, spread around the pan and almost disappeared - it turned the onions pink. Then I added a splash of base and
immediately added 2 heaped tsp chilli powder, 1/2 tsp of spice mix and just a pinch of gound methi. The spices cooked as the curry evaporated, and what was in the pan turned a deep red. I evaporated this almost dry and then splashed in some chicken stock and the rest of the gravy, and carried on as above. I left out the salt completely.
Also, breaking a rule of mine, but out of interest, I stirred in a good pinch of fresh coriander to the curry as it was simmering a couple of minutes before the end (with the rest added as above).
It really was quite good. I'm at the end of the batch now, but I'm going to have to try this again next time - perhaps a bit earlier in the evening (and a bit more sober! :

)