Mushroom and Swiss Sliders

Ingredients You’ll Need

• 1 1/2 lb (680 g) ground beef, 80–85% lean
• 1 tbsp Worcestershire sauce, divided
• 1 tsp kosher salt, divided
• 1/2 tsp black pepper
• 1/2 tsp garlic powder
• 1/2 tsp onion powder
• 2 tbsp olive oil
• 12 oz (340 g) cremini mushrooms, thinly sliced
• 1/2 small yellow onion, thinly sliced
• 2 garlic cloves, minced
• 1 tsp fresh thyme leaves or 1/2 tsp dried
• 1 package (12 count) slider rolls or Hawaiian-style rolls, still connected
• 8 slices (about 6 oz / 170 g) Swiss cheese
• 3 tbsp (42 g) unsalted butter, melted
• 1 tbsp chopped fresh parsley, optional

How to make mushroom and Swiss sliders

1. Step 1.

   Heat the oven to 400°F (205°C). Line a rimmed baking sheet with foil, then parchment.

2. Step 2.

   Using the connected rolls as a size guide, press the beef onto the lined sheet in an even rectangle about 1/2 inch larger on all sides than the slab of rolls and about 1/2 inch thick.

3. Step 3.

   Mix 1 teaspoon of the Worcestershire, 3/4 teaspoon of the salt, the pepper, garlic powder and onion powder and sprinkle evenly over the beef. Bake for 12–15 minutes, until cooked through to 160°F (71°C).

4. Step 4.

   Meanwhile, heat the olive oil in a large skillet over medium-high heat. Add the mushrooms in a single layer and cook without stirring for 3–4 minutes, until browned underneath.

5. Step 5.

   Add the onion and cook, stirring occasionally, for 6–8 minutes more, until the mushroom liquid has evaporated and both are deeply browned. Add the garlic, thyme, remaining 2 teaspoons Worcestershire and remaining 1/4 teaspoon salt and cook for 1 minute. Remove from the heat.

6. Step 6.

   Carefully drain the fat from the baking sheet and blot the beef with paper towels. Reduce the oven to 350°F (175°C).

7. Step 7.

   Slice the connected rolls in half horizontally and set the bottom half in a greased 9×13-inch baking dish. Top with 4 slices of Swiss.

8. Step 8.

   Trim the beef sheet to the size of the rolls and set it on the cheese in one piece, or cut it into large pieces and fit them together. Spread the mushroom mixture over the beef and top with the remaining 4 slices of Swiss.

9. Step 9.

   Replace the roll tops and brush with the melted butter. Bake for 12–15 minutes, until the Swiss is melted and the tops are golden.

10. Step 10.

    Sprinkle with parsley if using, let stand 3 minutes, then cut along the roll seams and serve warm.

One patty for twelve sliders

Ground beef sliders are often made with loose, crumbled beef, which is quick but tastes more like a sloppy joe than a burger. A mushroom Swiss burger needs an actual patty. Pressing the beef into a single thin sheet and baking it gives every slider a burger-style layer with no shaping or flipping. It cooks in about 15 minutes and slides into the rolls in one or two pieces.

Trace the size of the roll slab and make the beef slightly larger. Ground beef shrinks as it cooks, and a sheet that starts the same size as the rolls will leave the edge sliders with little meat.

Drain the beef well

A pound and a half of 80–85% lean beef releases a lot of fat on the baking sheet. Tilt the pan carefully to pour it off, then blot the top of the beef with paper towels before moving it. Skipping this step is the fastest way to greasy, soggy bottom rolls. The layer of Swiss beneath the beef adds another barrier.

Brown the mushrooms properly

The mushrooms carry most of the flavor in these sliders. Crowded and stirred constantly, they release water and turn gray and slippery. A hot skillet, a single layer and a few minutes without stirring let them brown first. The onion goes in once the mushrooms have color; its moisture would otherwise slow browning.

Keep cooking until all the released liquid has evaporated and the mushrooms look glossy and brown. Worcestershire added at the end deepens the savory, steakhouse-style flavor, and thyme and garlic add aroma without overpowering.

A 12-inch skillet is ideal. With a smaller pan, cook the mushrooms in two batches.

Swiss cheese choices

Deli-sliced Swiss melts evenly and has the mild, nutty flavor that defines this burger. Aged Swiss or Gruyère gives a stronger, more complex taste; both melt well. Cheese above and below the filling holds the sliders together, so the mushrooms do not fall out when the tray is cut.

Party planning

Bake the beef sheet and cook the mushrooms up to a day ahead. Refrigerate them separately and warm the mushrooms briefly before assembling. Cold fillings add about 5 minutes to the final bake; cover the dish with foil for the first half if the tops brown too quickly.

Assemble no more than a couple of hours before baking. The sliders are best served within 30 minutes of coming out of the oven. Chill any leftovers promptly; a foil-wrapped reheat at 350°F revives them better than the microwave, which leaves the Swiss rubbery.

Variations

Caramelized onions: cook the onion separately over medium-low heat for 25 to 30 minutes until jammy and sweet, then combine with the mushrooms.

Horseradish mayo: spread a thin layer of mayonnaise mixed with prepared horseradish on the top rolls before baking.

Turkey: ground turkey works in the sheet-pan patty. Add 1 tablespoon olive oil to the meat and bake to 165°F.