Is the Patty Melt the greatest sandwich in the world? I don’t know that I can make such a definitive claim, but I do know that it’s right up there with the best of them, and I also know that a favorite sandwich can make a mighty fine casserole. (See Reuben Casserole or Philly Cheesesteak Casserole or maybe even Runza Casserole.) Like those others, a Patty Melt’s beefy, savory, cheesy, almost greasy goodness translates incredibly to the casserole dish. This is piping hot comfort food that always pleases, just like its namesake sandwich.

Just in case you’re not familiar, a Patty Melt is a sandwich that consists of a ground beef patty (think hamburger), soft cooked onions, ooey-gooey cheese (usually Swiss), grilled bread, and a little more mayo and Thousand Island dressing than anyone is comfortable with. It’s greasy, it’s beefy, it’s good. And that’s exactly why it works in casserole form.

Our base layer here is bread, just like the sandwich. While white bread works fine, I’m partial to the slight tang of sourdough here. Just cube some up and line a 9×13 with it before topping that with Swiss cheese and browned ground beef.

The onions come next, and they take some time on the stovetop, but don’t rush it. You want them to be soft and sweet and lightly caramelized. They form an incredibly layer of flavor in this bake.

Next up is a Thousand Island dressing mixture that binds everything together and another layer of cheese. (I didn’t say this was health food.) The dressing binds everything together, but it also lends some tang and sweetness to something that is otherwise very, very rich.

The final flourish is a topping of breadcrumbs, made from the same bread you used for your base. You can pulse them really fine, but I like a little more texture in this application, so coarse crumbs are my go-to for this application. A little melted butter helps things along and you’ll end up with a golden brown, crispy casserole that’s full of beefy, savory flavor. It’s the kind of dish that’s bound to be a family favorite!