Quick Potato and Leek Soup recipe

I have spent a long time surfing the web trying to find some good easy and cheap recipes with very little success. Hence the perhaps seemingly odd inclusion of a recipe on my blog. It takes 15-20 mins to cook which includes the prep.time. Perhaps less if you are a better cook than me.

Ingreds: 340grams potatoes (about 6-8 med potatoes), sliced
1 onion, cubed
20gms marg/butter(about1 Tbsp)
1/2 litre beef broth (about 2 cups water and 1 cube of instant beef stock)
150gms of leek.(umm it's not much leek probably about a 1/4 of a stem), sliced
4 Tbsp cream
salt, pepper, nutmeg and chopped basil for seasoning according to taste. I don't use any.

1/ Melt marg. Add onions. Fry till clear
2/ Add potatoes. Cook with the occasional stir for about 5 mins.
3/ Add beef broth and the leek. Cook for 5 mins.
4/ Stir in cream.
5/ Season to taste
6/ Enjoy