Her genealogical sketch is here. She married Vladimir Petrovich Tolstoy. Her father, Vasily Orlov-Denisov, was a General of the Cossacks who was involved in the Napoléonic War of 1812 and later action.
From Wikimedia.
Sofia could be wearing a one piece under-dress with gold revers running from neck to hem. Her robes form an over-dress. The draw string around her waist prevents further assessment. The A on the blue order bow is for Tsaritsa Alexandra Feodorovna (1798-1860).
Keywords: 1835, Orlov - Pimen, Sofia Orlova-Denisova, София Орлова-Денисова, Orlov-Denisov family, Tolstoy family, Countess, Russian, Lady-in-Waiting, Alexandra Feodorovna (1798-1860), straight coiffure, jeweled kokoshnik, veil, earrings, fitted under-dress, bateau neckline, robings, quarter length full sleeves, buttons, full skirt, robes, Russian sleeves, draw string, over skirt