M & M Sandwich

I believe there may be a misunderstanding. There is no specific food item in the United States known as an "M & M sandwich" on a national scale. It's possible that there could be a regional or local dish by that name, or perhaps a specific restaurant has created its own dish using M&M's candy. However, without more specific information, it's difficult for me to provide detailed help.

Generally, an M&M's candy can be added as a topping or ingredient in various desserts, like cookies, cakes, or ice creams. If you're looking for a sandwich with M&M's, it might be a creative dessert sandwich, such as two cookies with M&M's inside or between them.

If you have a specific restaurant or location in mind, I'd be happy to look up more information about that particular "M & M sandwich."