Okroshka Day is observed in Russia every May 30, celebrating one of the country's most popular summer dishes, okroshka, a cold soup. The origins of this dish are unclear, but it is believed to have developed from botvinya, a cold soup made from leafy vegetables and sour kvass. The first recorded mention of okroshka dates back to the late 18th century, with early recipes including ingredients like pickled cucumbers and boiled vegetables. Traditionally, okroshka is made with kvass, though modern variations may use fermented dairy products or broths as substitutes. Common ingredients include various herbs, raw vegetables, boiled potatoes, hard-boiled eggs, and different types of meat or fish. The dish is typically served cold, and its preparation can vary by region and family tradition. Okroshka originated in the Volga region of Russia and is also popular in neighboring countries like Ukraine.