INGREDIENTS
4
4-inch portobello mushroom caps
1/8 tsp
Garlic
4
pieces Leaf lettuce, green
1/2 tsp
Onion
1
8 1/4-inch slices Plum tomatoes, ripe
3
Eggs plus 1 egg yolk
1/4 tsp
Kosher dill pickling brine
1 tbsp
Dijon mustard
3/4 tsp
Heinz ketchup
1/2 cup
Hellman\'s mayonnaise
1/8 tsp
Black pepper, freshly ground
1 pinch
Cayenne pepper
1 1/2 cups
Flour
1/2 tsp
Kosher salt
1 dash
Kosher salt
1/4 cup
Canola oil
4
Hamburger potato buns, toasted
2 cups
Panko breadcrumbs
1/2 cup
Cheddar, grated
1 1/2 cups
Muenster, grated
4 tablespoons ShackSauce (below)