Red lentil, tomato and sweet potato soup

This would have to be my second favourite soup. After lentil and barley with herbs from the garden. I developed this based on something I had at a friend's house back when I had the cafe. A reliable seller at lunch, it was a bit fancier then, with coconut milk and coriander (powder and fresh as as garnish). These days I tend to do a simple version, although sometimes I add coriander, cummin and a touch of chilli. A couple of weeks ago though I had a beetroot from the garden already washed and peeled in the fridge. I chopped it up and threw it in. Extra sweetness and an earthy undertone. And the best colour. Really, really good.

Ingredients

a medium sweet potato (peeled and sliced)
a tin of Italian chopped tomatoes
a big onion
garlic (I use about half a head if it isn't that strong, but we like garlic here)
grated ginger (about a teaspoon or two, enough to give a zing without being overpowering)
a cup or so of red lentils
a big old beetroot (optional but really good, peeled and diced)

To make

1. Roughly chop the onions and garlic. Saute with the ginger in some olive oil with a pinch of salt. This would be the point when I would also add powdered coriander or cumin if I was using them.
2. Add the tomatoes and saute briefly.
3. Add about a litre and a half of water, the red lentils, the sweet potato and the beetroot.
4. Cook at a slow roll until everything is good and tender. Blend with the bamix. Check for salt, although I find if you add some at the beginning it tends not to need any at the end but everyone is different with their salt.

And there you have it. Ridiculously easy and very nice for lunch or dinner.