1. In a bowl, combine Bragg's, water, oregano, and diced garlic; add portabellas and let sit in this mixture.
2. In another bowl, combine cornmeal, pepper, and salt.
3. Roll portabella in cornmeal mixture so that the portabella is completely coated and shake off any extra back into bowl. Dip in the Bragg's mixture again and then back into cornmeal mixture to get a nice, thick breading. Repeat with second portabella. Place mushrooms in small baking pan and drizzle with a little olive oil.
4. Bake in a 425 degrees F oven for 15 minutes, and then flip and bake for another 15 minutes. If breading looks too dry and isn't browning nicely, drizzle with a little more olive oil when you flip the portabellas.
5. Spread chipotle aioli on one side of each deli-style bun and add the lettuce, onion and tomato. Top with polenta-encrusted portabella and enjoy!
Variation: Instead of lettuce, red onion and tomato, Watercourse Foods serves this sandwich with coleslaw. The tangy coleslaw is an amazing compliment to the spicy chipotle aioli. A great variation to try, I just rarely have coleslaw made up when I want this sandwich.
Source of recipe: I wanted to recreate a sandwich I get at Watercourse Foods in Denver.