Apparently there's significant dialectal variation on whether the "hamburger" is a sandwich, including the bread, or just the meat often used to form the filling of a sandwich: https://en.wikipedia.org/wiki/Hamburger
In my usage, you can eat just a hamburger, but McDonalds won't sell you one; they'll insist on putting it between slices of bread, thus making a hamburger sandwich of it. If you want to eat just the hamburger, you'll have to peel off the bread and throw it away. They also sell fried-fish sandwiches and, in an absurd attempt to seem "healthy", chicken sandwiches.
Around here Starbucks serves mostly desserts, but that might be a regional thing.
Ok, definitely a dialect thing. A burger (~ patty if you insist) in a bun is just a burger, I don't think anybody here (UK) would call that a sandwich.
You can definitely convince McDonald's to sell you a hamburger on a plate without bread. A hamburger isn't a sandwich, but it is commonly served on a bun in sandwich form. Like how spaghetti is common served with sauce, and if you see that dish you just call it spaghetti, but if you see a plate of just the pasta it's still spaghetti.
In my usage, you can eat just a hamburger, but McDonalds won't sell you one; they'll insist on putting it between slices of bread, thus making a hamburger sandwich of it. If you want to eat just the hamburger, you'll have to peel off the bread and throw it away. They also sell fried-fish sandwiches and, in an absurd attempt to seem "healthy", chicken sandwiches.
Around here Starbucks serves mostly desserts, but that might be a regional thing.