Chef Julian Slowik projects his anger and frustrations on his oblivious guests through his food in The Menu, but he makes a surprising exception when he lovingly serves The Menu cheeseburger to Margot. Each course in The Menu was prepared by Slowik and his kitchen staff at Hawthorne. While the first three courses and their corresponding monologue evoke suspicion among the guests, the fourth instills panic and fear when a sous chef shoots himself before the elite clientele. With what follows, Slowik wreaks havoc in Hawthorne by revealing his sinister murderous plan for the evening.

https://screenrant.com/the-menu-movie-cheeseburger-meaning-explained/