Akuyaku Reijou no Chocolatier wa Oshi no Kouryaku ni Yuukou Deshita

Originally a pastry chef at a famous dessert shop, she tragically dies and is reincarnated into the world of an otome game, becoming Aegelia, the villainous heiress who rivals for the title of heroine. To survive in this world and to taste all her favorite desserts, she'll use her dessert knowledge and, incidentally, win over a marquis!? (Source: Kadokawa Taiwan, translated)