For the side dish, boil 2 cups (500 ml) of water with 1⁄2 TL salt. Cook rice in it according to package instructions. Sort the spinach, wash and drain. Fold into the rice about 5 minutes before the end of the cooking time.
For the bœuf stroganoff, clean, wash and slice the mushrooms. Wash the thyme and remove the leaves. Quarter the gherkins lengthwise. Dab steak dry and cut into fine strips.
Heat the oil in a large frying pan. Fry the steak strips in it for about 3 minutes until they are well done. Season with salt and pepper. Take out.
Sauté the mushrooms in hot frying fat and briefly fry the thyme. Dust the mushrooms with flour. Stir in 1 cup (250 ml) of water and sour cream. Add sugar and gherkins. Bring everything to the boil and let it boil down open for about 5 minutes.
Peel onion and cut into thin rings. Add the steak strips again. Season sauce with salt, pepper and lemon juice. Arrange rice and bœuf stroganoff with onion rings.