This is a classic clubhouse made meatless with pre-made vegan chicken and mushroom bacon. Stacks on stacks of wholesome of vegan goodness!
Preheat oven to 325°F.
To make the mushroom bacon, whisk together low-sodium soy sauce, water, maple syrup, liquid smoke, and smoked paprika in a large mixing bowl. Place the slices of portobello in the bowl with the marinade coating all sides. Let it sit for 15 minutes.
Place marinated slices onto a parchment lined baking sheet and bake for 15 minutes. Remove the baking sheet from the oven and flip the slices and brush some remaining marinade on them. Bake for another 15 minutes. While the mushroom bacon is cooking, you can prepare the remaining sandwich ingredients.
Over medium heat, brown the vegan chicken pieces in a pan with vegetable oil. This will take about 6 to 7 minutes, if from frozen. Slice the browned chicken pieces into strips.
To assemble one sandwich, add some mayonnaise to the bottom slice, then add a couple pieces of iceberg lettuce and sliced chicken. Then place the middle piece of bread next, which should have mayonnaise on both sides. Then stack 2 tomato slices, add ground black pepper to taste, place half the mushroom bacon on top, and then the last piece of bread with more mayonnaise on the inside.