When I was growing up, it was a tradition in our house to have potato soup for dinner on Christmas Eve. My mother never explained why, but since she rarely made it any other time, I'm thinking it had some special significance. Unfortunately, I never thought to ask her before she died in 1977.
This isn't her recipe, but one I've developed on my own over the years, and it's pretty close to the original.
1 large chopped onion
3 tbsp flour
3 cups water
3 cups potatoes, peeled and diced
3 tablespoons butter
1 1/4 tsp salt
1/4 tsp pepper
2 cups hot (not boiling) milk
In a large soup pot, saute the onion in the butter over medium high heat until transparent. Whisk the flour into the water and add it and all ingredients except the milk to the pot. Bring to a boil, then cover and reduce heat to low, stirring occasionally and cooking until potatoes are soft. Add the milk and adjust seasoning as desired, adding more butter if necessary. Top with grated cheese and enjoy!