Bollard, what a wonderful challenge!
I think your idea of rice and lentils is a good one - but, to make it more interesting, instead of adding tins of tomatoes, which is what I've always done until recently, why not add coconut milk and spice it up with a Thai curry paste?
I've made this several times in the last couple of weeks and it is absolutely gorgeous - my favourite meal of the moment. My daughter loves it - even without any spices, since she's BFing a 7-week-old!
Here's my recipe which would feed four:
100g red lentils
100g long grain white rice
1 onion, chopped
200g celery, chopped
200g shredded Savoy cabbage
1 red or green pepper
1 tin coconut milk (79p ATM, from Lidl - and better quality than Blue Dragon - IMO!)
Herbs and spices
Soy sauce, garlic paste and lemon juice
1 good dessertspoon vegan Thai curry paste (I use Geo Organic curry paste)
If you can't get vegan Thai curry paste, add cayenne pepper to taste
(Never used a slow cooker - you probably just throw everything in, switch on and leave it for a while, I'm guessing!
)
Here's what I do:
Method:
Put the rice and lentils on to cook - takes about 10 minutes
In a separate pan simmer the veg in a little water
Once they're both cooked through, combine the two and add the coconut milk and flavourings.
Whilst these are cooking, dry fry a teaspoon of cumin seeds for a minute or two - then add along with the rest of the ingredients. I use them whole, but next time I'll grind them in my spice grinder, see if that makes a difference.
All the very best - let us know how you get on, won't you!