In a frying pan, heat butter or olive oi over medium heat and add the finely chopped onion.

Fry slowly until transparent, do not brown.

Stir in garlic and spices (not the salt), then add chopped fresh tomatoes.

Pick through the lentils making sure to remove any bad ones.

Place the lentils in a sieve and rinse under cold running water.

Put into a large pot and add 6 cups water. Bring to the boil, skimming off the scum.

Once the lentils and water have come to the boil, add the onion mixture along with the dried black limes, each pierced with a fork (be careful when you do this) , also add the chopped, potato.

Return to the boil and boil gently, uncovered, for 20 minutes.

Add salt to taste, and a little more water if soup looks too thick.

Simmer gently for a further 25-30 minutes, uncovered, until the lentils and potato are tender, stirring occasionally.

Serve hot in bowls with lemon wedges on the side to squeeze on to individual portions.

Enjoy!