You need a really good stock/ bouillon cube as a base. Use your favourite and don’t over dilute.
Mine is not vegetarian normally as I use knot ham stock cubes, but that’s all you would need to change.
I make it in my Instant Pot pressure cooker , pressure cooking makes all the difference to lentils.
Use a mix of lentils - red, yellow split peas, green lentils.
Basic recipe
Large onion finely chopped
2 Large Carrots, finally chopped
swede or turnip - about equal measure to the carrots, finely chopped
2 sticks celery, finely chopped
I US cup ( 8 fl oz level on measuring jug) mixed lentils, thoroughly rinsed
1.7 l stock of choice
pinch of chilli flakes or small piece fresh ginger, finely grated ( about top segment of thumb size)
little pit of veg or groundnut oil
Saute the chopped veg in the oil for about 5 mins
Add the ginger or chilli
add the lentils, stir thoroughly
add the stock.
Switch to pressure cook - 20 mins
Leave to naturally release pressure
Once pressure is released, I purée with a stick blender
Alternatives -
add cumin or ground coriander , or even madras curry powder instead of ginger
use ready chopped soup pack from supermarket
add tin chopped tomatoes
Add bouquet garni.
My mother will be spinning in her grave if she can see this, but this is a staple in our house.