The Washington Post

Mushroom Reubens

Mushroom Reubens 2.000

Scott Suchman for The Washington Post; food styling by Lisa Cherkasky for The Washington Post

Feb 24, 2021

This take on the deli classic replaces the corned beef with slices of portobello mushrooms for a satisfying sandwich featuring zesty Russian dressing, melty Swiss cheese and tangy sauerkraut. Pressing the sliced mushrooms in a skillet eliminates excess moisture while retaining a juicy bite, and a mustard-and-spice paste incorporates some of the flavors you would otherwise find in the typical corned beef. The number of slices you end up with will depend on the size of the portobellos. Expect from 8 to 16 slices total.

If you don't feel like making the Russian dressing from scratch, substitute your favorite store-bought variety.

Total time: 1 hour

Storage Notes: Leftover dressing can be stored in an airtight container for up to 3 days. Extra mushrooms can also be refrigerated for a few days for additional sandwiches, though you may want to warm them slightly or allow to come to room temperature before using.


When you scale a recipe, keep in mind that cooking times and temperatures, pan sizes and seasonings may be affected, so adjust accordingly. Also, amounts listed in the directions will not reflect the changes made to ingredient amounts.

Tested size: 2 servings; makes 2 sandwiches

  • For the dressing
  • 1/4 cup mayonnaise
  • 1/4 cup ketchup
  • 1 1/2 teaspoons prepared (white) horseradish or peeled, freshly grated horseradish root, patted dry
  • 1/2 teaspoon hot paprika (may substitute sweet paprika and a pinch of cayenne pepper)
  • 1 tablespoon finely chopped pickles (may substitute pickle relish)
  • 1 clove garlic, minced
  • For the mushrooms
  • 2 tablespoons Dijon mustard
  • 2 teaspoons ground coriander
  • 1 teaspoon brown mustard seeds
  • 1/2 teaspoon kosher salt
  • 1/4 teaspoon red pepper flakes
  • Pinch ground allspice
  • Freshly ground black pepper
  • Vegetable oil
  • 1 pound portobello mushrooms, sliced in half horizontally
  • For the sandwich
  • 4 slices rye bread (seeded, seedless or marble)
  • 4 slices Swiss cheese
  • 2/3 cup sauerkraut, drained
  • 1 tablespoon unsalted butter (may substitute salted butter)


Make the dressing: In a medium bowl, using an immersion blender, process the mayonnaise, ketchup, horseradish, paprika, pickles and garlic, pulsing until well combined. (You can also use a food processor, but consider doubling the batch for easier processing.) The yield is about 1/2 cup; you'll have extra for more sandwiches or other uses. Transfer to an airtight container and refrigerate until needed.

Make the mushrooms: In a small bowl, stir together the mustard, coriander, mustard seeds, salt, red pepper flakes, allspice and a few grinds of black pepper until thoroughly combined.

Coat the bottom of a 12-inch nonstick skillet with a thin layer of oil and set over medium heat for several minutes, or until you feel a decent blast of heat when holding your hand an inch or so above the skillet. Arrange the mushrooms in the skillet in two layers. Wrap the bottom of a cast-iron skillet or a plate (weighted with heavy cans) in foil and place on top of the mushrooms; the goal is to press the liquid out of the mushrooms. Cook, undisturbed, for 6 minutes. Remove the skillet or plate, flip the mushrooms over, arranging them so the thickest slices are toward the middle, or the hottest part of the pan. Return the skillet or plate on top of the mushrooms and cook until the mushrooms have significantly reduced in size and almost all the liquid has evaporated, another 5 to 6 minutes. If there's still liquid in the skillet, uncover the mushrooms, briefly increase the heat to medium-high and cook until the water is mostly gone.

Transfer the mushrooms to a platter and spread an even, thin layer of the mustard mixture on one side of each mushroom slice. (On the slices from the top halves of the mushrooms, the mixture adheres best to the exterior rather than the flesh.)

Wipe out the skillet, add another thin coating of oil and return to medium heat (no need to preheat more than 1 minute or so, as it will still be quite hot). Place the mushrooms in a single layer, coated side down, and cook until browned and crisp in spots, 2 to 3 minutes, working in batches. A little of the coating may come off; that's okay — just pile it on when assembling the sandwiches. Wipe the skillet clean.

Make the sandwiches: Spread about 1 tablespoon of the dressing on each of the 4 slices of bread. On 2 of them, build the sandwiches, evenly dividing the cheese, mushrooms and sauerkraut, followed by the other 2 slices of bread.

In the skillet over medium heat, melt the butter until bubbling slightly. Griddle the sandwiches on both sides (do one at a time if you're tight on space) until golden brown and crisp, 2 to 3 minutes per side. Cut in half and serve.

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Recipe Source

From Voraciously staff writer Becky Krystal; dressing recipe adapted from cookbook author John Holl.

Tested by Becky Krystal.

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Nutritional Facts

Calories per sandwich: 548

% Daily Values*

Total Fat: 25g 38%

Saturated Fat: 14g 70%

Cholesterol: 67mg 22%

Sodium: 1899mg 79%

Total Carbohydrates: 57g 19%

Dietary Fiber: 7g 28%

Sugar: 18g

Protein: 26g

*Percent Daily Value based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.

Total Fat: Less than 65g

Saturated Fat: Less than 20g

Cholesterol: Less than 300mg

Sodium: Less than 2,400mg

Total Carbohydrates: 300g

Dietary Fiber: 25g

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