White Borscht - cooking recipe

Ingredients

1 lb Polish sausage
1 1/2 quarts water
1 quart buttermilk
1 cup milk
1 egg
3 tablespoons flour
salt
boiled potatoes (optional)
hard-boiled egg (optional)
prepared horseradish (optional)

Preparation

Place water in a large pan.
Add sausage and bring to a boil over high heat.
Reduce heat to low-simmer and cook, covered, for 30 minutes.
Remove sausage, reserving cooking liquid, and set sausage aside to cool.
Add buttermilk to cooking liquid and return to boil, reduce heat to low and simmer.
In a medium bowl, combine milk and egg.
Gradually whisk in flour and stir until smooth.
Add 3 tablespoons of the simmering soup base to the milk-egg mixture and stir to combine (this tempers the egg so it doesn't curdle when added to the soup base).
Slowly drizzle milk-egg mixture into the simmering soup, whisking continuously until all has been added, continue to simmer until soup has thickened.
Add salt to taste.
Serve with reserved Polish sausage.
May also be served with boiled potatoes, slices of hard boiled egg and a dollop of prepared horseradish.