SWEET AND SOUR
Sauté an onion in oil, then add a tablespoon of flour. Once it turns golden brown, gradually stir in a cup of broth, mixing continuously. Next, add salt, pepper to taste, one and a half tablespoons of vinegar, a tablespoon of raisins, and an equal amount of sugar. Simmer on low heat for 5-10 minutes. If you prefer, you can substitute the raisins with finely chopped pickles, but in that case, skip the sugar.
MUSTARD SAUCE
Heat half a tablespoon of oil and mix it with an equal amount of flour. Dissolve half a cup of sour cream (a thicker, tangier version of sour cream common in Eastern European cuisine) and broth into the mixture. Add salt, pepper, and mustard to taste. Bring everything to a boil.
MUSHROOM SAUCE
Boil 4 dried mushrooms, then in a tablespoon of heated oil, sauté a tablespoon of flour. Gradually add the mushroom broth, along with salt, pepper, and finely chopped cooked mushrooms. Stir in half a cup of sour cream and bring to a boil once.
COLD HORSERADISH SAUCE
Grate horseradish and drizzle it with vinegar, adding salt to taste. Mix in fresh sour cream, and if desired, you can add sugar.