Turnip and Jerusalem Artichoke Soup

2 medium onions, chopped (leeks are also okay)
1 tablespoon olive oil
1 small turnip, peeled and chopped
1 lb jerusalem artichokes, peeled and sliced
4 ounces split red lentils
2 pints vegetable stock
1 bay leaf
salt and pepper

When you are preparing the artichokes, drop them into water with a bit of lemon juice or vinegar as you go so they don't discolour. Drain before adding to the recipe later.
Start the soup by sauteing the onions in the oil for a couple minutes.
Add the turnips and artichokes. Fry for 3 - 4 minutes, then put the lid on and sweat for 5 minutes, stirring once or twice to avoid sticking.
You may need to add 1/4 cup water if things start to stick to the pot.
Rinse the lentils in a sieve then add to the vegetables with the stock. Stir well and bring to the boil.
Boil for 10 minutes, then reduce heat to a gentle simmer. Simmer for about 25 minutes.
Remove the bay leaf.
Liquidise if preferred, then season to taste.