The Dark Cooking Method of the Villainous-Sister Noblewoman

Marie, engaged to her lover, is constantly undermined by her younger sister Michelle, who acts like the “cute, innocent” sibling to mask darker intentions. When Marie is pushed to the brink by persistent sabotage and betrayal, Yuri — her childhood friend and a genius magic researcher — steps in to help her get revenge. They team up, and Marie soon presses forward with a “dark cooking method” — a plan of clever retaliation that overturns expectations.

https://comic.k-manga.jp/title/231883/pv