This vegetarian club gets an extra boost of flavor from miso mayonnaise and salty, chewy mushroom bacon. Eating one has no bearing on your membership in the club mentioned above.
Mash together with a fork in a small bowl until smooth:
Lay out on a countertop:
Spread the mayonnaise mixture on the inside of all 4 slices of bread (you will have extra—reserve it for another use). Divide between 2 of the pieces of bread:
Top with the remaining bread slices.