Double-Stack Mushroom and Chicken Cheeseburgers

Ingredients

• 1 lb. crimini mushrooms, halved if large
• ½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt, plus more
• 1 lb. ground chicken or turkey, preferably dark meat
• Vegetable oil (for grill and drizzling)
• 1 small onion, trimmed, sliced crosswise into 4 rounds
• Freshly ground black pepper
• 8 thin slices Muenster
• 4 potato buns
• 4 Tbsp. mayonnaise
• 4 Tbsp. curry mustard (such as Brooklyn Delhi) or other mustard
• Bread-and-butter pickles and shredded iceberg lettuce (for serving)

Description

Step 1

Pulse mushrooms with ½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt in a food processor until very finely chopped. (Alternatively, finely chop mushrooms by hand, then toss with salt in a medium bowl and let sit 2 minutes.) Transfer mushrooms to a clean kitchen towel, gather ends together, and wring over bowl to remove as much moisture as possible. Reserve liquid for another use.

Step 2

Mix mushrooms and chicken in a large bowl with your hands until well combined. Divide mixture into 8 balls and gently form into patties about ¼" thick. Transfer to a parchment-lined baking sheet.

Step 3

Prepare a grill for high heat; lightly oil grate. Drizzle onion with oil and season with salt. Grill on cooler edges of grill, turning occasionally, until slightly softened and charred, about 8 minutes. Transfer onion to a platter.

Step 4

Season tops of patties with salt and pepper. Place, seasoned side down, on grate and season second side with salt and pepper. Grill until edges are browned, about 2 minutes. Flip and top with cheese. Grill until patties are cooked through and cheese is melted, about 2 minutes. Transfer patties to platter with onion.

Step 5

Grill buns, cut side down, until lightly charred, about 30 seconds. Spread cut sides of bottom buns with mayonnaise and top buns with mustard. Layer pickles, grilled onion, 2 patties, and lettuce on bottom buns, then close up burgers.