2 tbsp oil 
1 large onion -- chopped 
1 carrot -- chopped 
2 sticks celery -- chopped 
8 oz red lentils -- (1 cup) 
3 pints boiling water 
2 veg stock cubes 
2 tsp dried mixed herbs 
1 c tomatoes, tinned, fresh,juice or puree -- add at 
end 2 tsp salt -- add at end 
1/4 c nutritional yeast flakes (optional) -- add at end 

Chop the veg in the food processor and then fry in the
pressure cooker until softened. Add boiling water, stock
cubes, lentils and herbs. Bring to the boil, cover and bring
up to pressure. Cook 20 mins (at 15lbs pressure). (If no
pressure cooker, cook for 1 hour). Remove from heat and
leave to cool - I do this without releasing the pressure.
Add something tomatoey and salt to taste (I use no salt
stock cubes, so you may need to adjust this). I sprinkle
nutritional yeast flakes in before serving. This gives it a
nice earthy taste. This freezes well. I think the flavour
improves if the soup is left to sit on the stove for a
while. It is fairly smooth but some children prefer it
liquidised. It is almost as good if you miss out the oil and
the frying.