Wipe the mushrooms clean, then slice them.
Heat 3 tbsp. of olive oil in a frying pan over medium-high heat. Add the mushroom slices, season with salt and pepper, and sauté until well softened. Remove from the heat.
Wipe out the same pan with paper towel and cook the “Elaiopoulaki” chicken burgers for 5–6 minutes per side until done.
Split the brioche buns. Spread mayonnaise on the bottom halves. Divide and pile on the sautéed mushrooms. Add a chicken burger to each bun, top with xynomizithra cheese, spread mustard on the top halves of the buns and close the burgers.
Bite in and enjoy!
