I found this recipe at Serious Eats and just had to try it. This burger is so good! It has a nice juicy burger, a stuffed Portobello Mushroom, Lettuce & Tomato and Shake Shack Sauce on top.
1 lb beef, divided into 4 loosely formed balls
4 portobello mushroom caps, 4 inches across
4 oz grated muenster cheese
1 cup panko breadcrumbs
1 cup all-purpose flour
1 egg, beaten
4 slices American cheese
2 Martin’s potato rolls, toasted
2 leaves green leaf lettuce
2 slices of tomato
2 tablespoons shack sauce or other condiments
salt + pepper
oil, for frying
Shake Shack Sauce:
1/2 cup mayonnaise
1 tablespoon ketchup
1 tablespoon yellow mustard
4 slices kosher dill pickle
1/4 teaspoon garlic powder
1/4 teaspoon paprika
Pinch cayenne pepper
Divide beef into four loose balls, put in refrigerator. Slice tomatoes and clean lettuce. Refrigerate until ready to use.
Steam mushrooms for 8-10 minutes. After steaming, press with paper towels to remove any excess water. You can also cook these in the microwave for about 4 minutes between 3 layers of paper towels, sandwiched between two heavy bottomed plates. Be careful removing plates from microwave, they most likely will be hot. Once the mushrooms are cooled, press between paper towels to remove any excess water.
Grate cheese and roll into two ball shapes. Stuff each cheese ball between two mushroom caps. Using plastic wrap, press the mushrooms together by twisting the plastic wrap as if you were wrapping candies. The mushroom should form a little puck. Place in fridge.
Put flour, panko and egg wash in three separate bowls. Dredge mushroom patties in flour, egg wash and panko. Repeat with egg wash and panko breadcrumbs for a second dip. Let the patties rest in the refrigerator for 5-10 minutes before frying. Fill oil about half way up in a cast iron skillet and preheat to 375 F. Fry mushroom patties for 2-3 minutes or until golden brown on one side before flipping. Cook the other side for 2 minutes before removing from pan. Salt and drain on a wire rack.
While the mushroom is cooling, heat a large skillet on medium-high heat. Season burgers with salt and pepper and place, seasoned side down, on the hot griddle. Using a flat spatula, flatten the burger to form a thin patty. Flattening with the spatula also creates a nice crust on the burger. Cook for 1-2 minutes before flipping. Since these burgers are thin, they cook fast. After you flip the burgers, season the top with salt and pepper then place a slice of cheese on each patty. Cook for 1-2 additional minutes.
SHAKE SHACK SAUCE
Remove burgers from pan and stack it on some Martin’s potato rolls, add your ‘Shroom burger along with lettuce, tomato and ShackSauce and you’ve got yourself a homemade Shack Stack!