Before the pandemic, you could wander into Du-par’s, on the corner of Fairfax and Third in Los Angeles, ask for a seat in a slick, red, tufted vinyl booth, and be sipping a mug of hot coffee in less than a minute.

You could order a stack of the diner’s famous pancakes, fat as throw pillows, a small bowl of melted butter on the side. You could feast on dense slabs of French toast, soft tuna sandwiches, ice-cold chocolate malts, wedges of cherry pie, “big, Frisbee-shaped omelets gilded with American cheese, soft rolls as large as spaniel ears … Swedish meatballs on Wednesdays and roast turkey with dressing,” as Jonathan Gold wrote in the Los Angeles Times in 1994. You could, if you were in the mood, order a patty melt.

Du-par’s probably didn’t invent the patty melt, but it claims to serve the original recipe. On the menu, it’s listed as “Tiny’s Classic Patty Melt: The Original Since 1932.” A beef patty, smothered in caramelized onions and melted Swiss, peeks out from between two slices of rye, griddled until crisp on both sides.

I used to live a block from Du-par’s – which reopened with limited indoor and outdoor seating last summer – and when I was having a bad day, I ordered the patty melt with french fries. On good days, I got it with coleslaw and extra pickles. I still love that play among the rich, buttery sandwich, soft tang of the slaw and sour punch of the pickles. An Arnold Palmer on the side, a slice of pie for dessert, extra coffee if I had time to linger. Diners!

In honor of diners, how about we make patty melts tonight? This recipe is a bit of a cheat, because it sidesteps the traditional “patty” for meaty, crispy mushrooms. You can use any mushrooms you like, but it’s wild mushroom season in most of the United States now, so if you see maitakes, king or black trumpets, hedgehogs or porcinis at the market, use those. Whatever ones you pick, the mushrooms will get a boost of flavor from Worcestershire sauce. Caramelized onions go in, too, of course, as does a pretty generous amount of cheese. Pile everything between two slices of bread and fry the sandwiches in a smidge of butter until they’re golden on both sides. Slice – on the diagonal! – and serve with … potato chips? A short milkshake? A quickly tossed slaw or herby salad? In my humble opinion, you should never skip the pickles.

As with all sandwiches, you can change up just about any element in this mushroom melt. Swiss is traditional, but use whatever melty cheese you happen to have kicking around in the fridge. I think the caramelized onions are essential, but consider instead caramelized garlic or fennel. I only ever make patty melts on rye bread, but Texas toast, multigrain, gluten-free or plain old white pullman can work, too.

If you don’t cook mushrooms too often, know that they will steam first, releasing excess moisture, before they caramelize alongside the onions. Onions have some natural sugar that will help them caramelize; if you skip the onions for any reason, consider adding a pinch of sugar to the mushrooms toward the end of cooking them, to ensure extra-crisp edges.

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Mushroom Patty Melts

30 minutes

4 servings

The patty melt is a diner classic, but it doesn’t have to be so meaty. This version puts deeply caramelized mushrooms and onions front and center. (You can add a beef patty, too, if you want.) A splash of Worcestershire sauce adds acidity and rounds out the flavors. Use your favorite cheese and bread, but don’t skimp on the butter, which ensures the best flavor and a crispy exterior.

INGREDIENTS

6 tablespoons (3 ounces) unsalted butter, divided

2 tablespoons olive oil

10 ounces mushrooms, such as cremini mushrooms or baby bella, sliced

1 large yellow onion, halved and thinly sliced

1/4 teaspoon kosher salt

4 teaspoons Worcestershire sauce

8 slices rye bread or another bread of choice

8 slices Swiss cheese or Gruyère cheese, or more as desired

Pickles, for serving (optional)

DIRECTIONS

In a large (ideally 12-inch wide cast iron) skillet over high heat, melt 2 tablespoons of the butter. Add the olive oil, mushrooms, onion and salt. Fry, stirring frequently, until the onions and mushrooms caramelize and crisp, 10 to 15 minutes, adjusting the heat as necessary if they start to burn. Remove from the heat and stir in the Worcestershire.

Assemble the sandwiches: Lay 4 slices of bread onto a flat surface. Place at least 1 slice of cheese on each slice of bread. Top with a quarter of the onion-and-mushroom mixture, followed by at least 1 slice of cheese and the remaining slice of bread.

Wipe the skillet out and place over medium heat. Melt the remaining 4 tablespoons of butter, and fry the sandwiches, in batches if necessary, until the cheese has melted evenly and both sides are crisp, 2 to 3 minutes per side. Slice in half and serve hot, with pickles on the side, if desired.

Nutrition | Calories: 622; Total Fat: 41 g; Saturated Fat: 22 g; Cholesterol: 97 mg; Sodium: 660 mg; Carbohydrates: 41 g; Dietary Fiber: 5 g; Sugars: 7 g; Protein: 23 g.

Recipe from staff writer G. Daniela Galarza.