Like paellas and tagines, casseroles take their name from the dish they're cooked in. But, while anything baked in a casserole can be called a casserole, the Midwestern preparation known as "hotdish" is much more specific. A hotdish always consists of meat, vegetables, a starch, and sauce—it's not a side dish, but an entire meal unto itself. And Tater Tot hotdish is, hands down, the most epic version of these one-pot wonders.
A traditional Tater Tot hotdish can feed a crowd with little more than a handful of supermarket staples, a skillet, a baking dish, and a few minutes of your time. It typically starts with ground beef, which is mixed with canned or frozen vegetables, covered in condensed soup, and topped with frozen Tater Tots. Bake it in the oven until it's crisp and bubbly, pass the ketchup, and dinner is served!
My from-scratch version takes a little more time and effort, but it lets you ditch the cans for a fuller-flavored, fresher twist on the family favorite. I couldn't help but notice the uncanny similarities between Tater Tot hotdish, shepherd's pie, and moussaka, so I drew a little inspiration from those dishes for my recipe. I moisten the ground beef base with a quick gravy and season it with a splash of Worcestershire sauce, just as you would the lamb in our shepherd's pie. And I replace the condensed soup with a thick layer of mushroom béchamel, like the one that tops moussaka.
It all starts with that rich and creamy mushroom béchamel. Béchamel is a milk sauce that's thickened with flour and butter. It's incredibly versatile—you'll find it in the base for macaroni and cheese, spooned between layers of lasagna, and worked into countless other crowd-pleasing dishes. Because the basic formula for béchamel is so simple, it's a cinch to jazz it up. One of my favorite tricks is to infuse the milk with other ingredients, which allows you to change the flavor while maintaining that smooth and silky texture.
In this case, I roast mushrooms until they're deeply browned, then steep them in milk until they've surrendered all their savory flavors. I tested this recipe with a range of mushrooms, like shiitakes, maitakes, porcinis, and morels, only to find that the best flavor came from the unassuming button mushroom. These shy little guys speak up with that deep, iconic mushroom flavor you expect from cream of mushroom soup. After soaking them in milk for an hour, I simply strain them out and discard them. They've given you their all and are ready for the compost pile at this point.
The mushroom-y milk, on the other hand, is just getting started. I combine flour and butter in a saucepan, stirring over medium heat until it forms a roux—a simple paste with incredible thickening powers. Though some roux are cooked until they turn a deep brown, this sauce doesn't call for such a dark, toasty flavor. After about five minutes, the raw, starchy aroma of the flour subsides, at which point I start adding the mushroom milk, whisking in just one tablespoon at a time. If you're patient at this stage, there'll be no need to strain out lumps or clumps, because your béchamel will be smooth and perfect straight from the pot.
Next, I turn to the meat. Instead of using plain ground beef, I get a little saucy—extra moisture helps the beef hold up to the Tot-baking time. I begin by searing the ground beef over high heat, using a generous amount of oil to maximize crunchy bits and browned flavors. Depending on its meat-to-fat ratio, your ground beef may release a lot of fat; for better browning, though, it's always best to start with plenty of oil in your skillet and drain excess fat off afterward as needed.
Unfortunately, there's always a trade-off between flavor and texture when you're cooking ground beef. Searing in a hot pan develops rich brown flavor at the expense of juicy meat. The addition of broth allows you the best of both worlds, so, after sweating some onion and garlic in the skillet, I add a spoonful of flour and a splash of chicken broth, which thicken into a savory gravy. Off the heat, I stir in sweet peas and corn, spicy mustard, and fresh herbs to perk up the ground beef filling.
It all comes together in a baking dish. Spread the meat mixture evenly into the dish, top with the mushroom béchamel, and arrange the Tater Tots on top. You can follow Kenji's recipe to make your own Tots if you like, but my love for Ore-Ida runs deep and pure. Bake the casserole until it's bubbly and golden brown. Then invite over a Little League team, or book club, or the neighborhood watch, because this is a dish meant for sharing.