This is one of those creamy soups made without any cream that I love so much. This time it is a pea soup, beautifully green and delicious, but relatively fat-free. The potato adds the creaminess to the mixture.
In a large saucepot, saute the onion in the olive oil 5 minutes. Add the broth, seasonings, and potato. Bring to a boil and coook until potato is tender, about 10 minutes. Add the peas and cook 5 minutes longer.
Puree the soup. You may use an immersion or regular blender to do this or a food mill. If using the immersion blender I prefer to strain the soup to take out the pea coverings using a fine sieve. The food mill does this for you.
To serve: Soup may be served hot or cold. Top each serving with a swirrl of plain non-fat yogurt.