Add this code to the Custom CSS field on the Style tab of your Restaurant Menu widget’s settings:
.RestaurantMenu__Component-sc-1ch5kvj-0 {
background-image: url("https://www.purina.co.uk/sites/default/files/styles/ttt_image_original/public/2023-03/Hero Pedigree Cats.webp?itok=zKKx3jSn");
background-repeat: no-repeat;
background-size: cover;
background-position: center;
}
Note: Do not forget to replace the url in the code with the link to your image