Why It Works
- Steeping the milk with deeply roasted mushrooms makes for a flavorful mushroom sauce.
- Worcestershire sauce gives the ground beef extra depth and umami.
- Spicy Dijon mustard perks up all the rich ingredients.
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 and shepherd's pie, so I drew a little inspiration from this dish 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.
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 mushrooms. 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 thickens 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.
For the Mushroom Sauce:
5 cups (570g) button mushrooms, washed, dried, and quartered
2 tablespoons (30ml) extra-virgin olive oil
12 sprigs thyme, divided
Kosher salt and freshly ground black pepper, to taste
2 1/4 cups (450g) whole milk
1/2 onion (125g), peeled and roughly chopped
2 cloves (8g) garlic, smashed
2 tablespoons (28g) unsalted butter
3 tablespoons (25g) flour
For the Ground Beef:
1 tablespoon (15ml) vegetable oil
1 pound (454g) 90% lean ground beef
1 small (250g) onion, diced
2 cloves (8g) garlic, finely minced
1 tablespoon (8g) all-purpose flour
3/4 cup (180ml) chicken stock, either homemade or low-sodium store-bought
3/4 cup (100g) frozen or fresh peas
3/4 cup (100g) frozen or fresh corn kernels
1/4 cup (30g) chopped parsley
1/4 cup (30g) chopped chives
1 tablespoon (15g) Dijon mustard
2 teaspoons (10ml) Worcestershire sauce
1 pound (454g) Tater Tots, frozen or homemade
Ketchup, for serving
For the Mushroom Sauce: Adjust oven rack to center position and preheat oven to 350°F (180°C). In a large bowl, toss mushrooms with olive oil and 6 sprigs thyme, then season with kosher salt and freshly ground black pepper. Spread seasoned mushrooms on a foil-lined rimmed baking sheet. Bake until deeply browned, about 45 minutes. Discard thyme sprigs and increase oven temperature to 375°F (190°C).
In a medium saucepot, combine roasted mushrooms with 6 remaining thyme sprigs, milk, onion, and garlic and bring to a boil. Remove from heat and steep, covered, for 1 hour. Strain, pressing gently on the solids.
Wipe out pot and return to stovetop. Melt butter over medium heat until foaming subsides, then add flour and mix into a paste. Continue cooking until raw flour smell is gone, about 5 minutes. Whisking constantly, add mushroom-infused milk in a thin, steady stream, or in increments of a couple of tablespoons at a time, whisking thoroughly and getting into all corners of the pot to maintain a homogeneous texture. Sauce will initially become very thick, then get very thin once all milk is added.
Heat, stirring, until sauce comes to a simmer and begins to thicken slightly, about 10 minutes. Reduce heat to low and cook, stirring, until sauce is thick enough to coat the back of a wooden spoon, about 3 minutes. Season to taste with kosher salt and freshly ground black pepper.
For the Ground Beef: In a large skillet, heat oil over medium-high heat. Add ground beef and break up into crumbles with a whisk or potato masher. Cook until well browned, 5 to 10 minutes. Drain off any excess fat, leaving only about 1 tablespoon (15ml) in skillet along with meat.
Reduce heat to medium, add onion and garlic to ground meat, and cook for about 2 minutes. Add flour and cook an additional minute, until blond. Add chicken stock and simmer until thickened, about 3 minutes.
Remove from heat and finish ground beef mixture with peas, corn, parsley, chives, Dijon, and Worcestershire. Season to taste with kosher salt and freshly ground black pepper. Scrape meat mixture into a 2-quart baking dish.
To Finish: Top meat with mushroom sauce and arrange Tater Tots on top. Bake for 30 minutes, or until Tater Tots are crispy and golden brown. Serve with squiggles of ketchup.
|Nutrition Facts (per serving)|
|Servings: 6 to 8|
|Amount per serving|
|% Daily Value*|
|Total Fat 23g||29%|
|Saturated Fat 7g||36%|
|Total Carbohydrate 35g||13%|
|Dietary Fiber 5g||16%|
|Total Sugars 8g|
|Vitamin C 18mg||88%|
|*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.|