Bust out the barbecue sauce, 'cause it's officially summer! For non-meat-eaters, seitan is a great replacement. It's savory and the texture is much more pleasant than that of tofu. This sandwich is super easy to make and you can experiment with different toppings.
In a small sauté pan, toss the seitan in barbecue sauce over medium heat until heated through, about 5 minutes. Divide the seitan evenly on each bun. Top with the red onion and avocado. Enjoy!