Step 1

Preheat oven to 425°F (220°C). Line a rimmed baking sheet with parchment paper. Set aside.

Step 2

In a large mixing bowl, add tamari, balsamic vinegar, water, Worcestershire sauce, smoked paprika, onion powder, and garlic powder. Stir well to combine.

Step 3

Clean mushrooms and slice into 1/2" strips. Then add them to the large bowl and gently toss with a spatula to coat with the marinade. (It's okay if some mushrooms break.)

Step 4

Lay out the marinated mushrooms single file on your lined baking sheet. (Feel free to spoon any leftover marinade over the top of the mushrooms on the sheet.) Bake for 25 minutes or until desired tenderness.

Step 5

Assemble sandwiches: Lightly toast your bread if desired. Then spread about 1 Tbsp. aioli, or more, on each slice of bread. (Spreading it on both sides acts as a helpful "glue" holding the sandwich together.) Then on one slice, layer some mushroom strips, 1/2 cup arugula, and some roasted red pepper. Place your other bread slice on top.