Beef tenderloin - 1 lbs. (0.49 kg)
salt - 0.25 teaspoon
pepper - 0.125 teaspoon
2 yellow onions
sour cream - 0.5 lbs. (230 g )
flour - 1 tablespoon
butter - 1 tablespoon

Prepare sauce: boil 1 glass of water. Carefully add flour stirring continuously. Boil 10-15 minutes. Add sour cream and salt. Bring to a boil. Put aside. Chop onions and simmer them with butter at low temperature for 20 minutes. Mix with the sauce. Cut beef into sticks 1.5 -2 in. (4-5 cm.) long and 0.2 in. (2-3 mm) wide. Add salt and pepper. Thoroughly fry at high temperature for 10 minutes and another 10 minutes at low temperature. Add the sauce mixed with onions. Fry for another 5 minutes. Servings: 2-3 with any garnish.