Create a highly realistic 3D model of a potato mascot with arms, legs, eyes, and a mouth, maintaining the characteristic potato appearance. The mascot should wear a chef's hat and be depicted with one arm raised, hand formed into a simple fist with three fingers closed and one finger extended upwards in a 'thumbs up' gesture, while the other hand remains completely closed. Ensure the mascot maintains a cheerful expression with bright eyes and a warm smile. The background should be plain white to highlight the mascot.