Adapted from this.
Grill up portobellos, onions, and bell pepper. In a small pan mix 1/4 c water, 1 tbsp soy sauce, 2 tbsp flour, and 1 tsp chicken bullion, and simmer until thick. Slather bread with sauce, veggies, and top with shredded vegan cheese. Toast in the oven until crispy.
Indulge in an amazing lunch, and savour every crunch. No rhyme intended.