Start by cleaning your portobello mushroom caps. Remove the stems and gently scrape out the gills with a spoon. This helps in getting rid of any bitterness and allows for more stuffing. Brush the caps with canola oil, salt, and pepper on both sides. Set them aside while you prepare the filling.

In a bowl, mix together the cheeses, minced onion, garlic, smoked paprika, and a pinch of sea salt. This cheesy goodness is what makes the burger so irresistible. Make sure it’s combined well.

Take the cheese mixture and generously stuff it into each mushroom cap. Press it down gently, ensuring you have a good amount filling.

In one bowl, place 1 ½ cups of flour. In a second bowl, whisk together the eggs and yolk. Finally, in a third bowl, add the panko breadcrumbs.

First, dredge each stuffed mushroom cap in the flour, shaking off the excess. Next, dip it in the egg mixture, covering it thoroughly. Lastly, coat it with the panko breadcrumbs, ensuring it’s evenly covered.

Heat the canola oil in a frying pan over medium-high heat. Once hot, carefully place the breaded mushrooms in the pan. Fry for about 3-4 minutes on each side, or until golden brown and crisp. Remove them from the pan and place them on paper towels to absorb any excess oil.

While the mushrooms are frying, lightly toast your potato hamburger buns. You want them warm with a slight crust. This will hold up well against the moist shroom burger.

Lay a crisp piece of lettuce on the bottom half of each toasted bun. Place the golden-brown fried mushroom on top, add two slices of tomato, and sprinkle with chopped basil. Drizzle or spread ShackSauce on the top bun, then place it over the stack.