It is funny that this recipe is actually a meat recipe from Eating Well. The beauty of meatless meals is that it is easy to change one with meat to one without meat. They still often work. I did not substitute anything for the meat but if you choose to, tofu could be used.
Since, we cut back on our meat intake, I have simply omitted it from most of the dishes but there are times when a little crunch or some bulk makes a difference. It might be as simple as adding some nuts or additional vegetables or a bit of quinoa.