i second all of the above. i don't like popcorn so i wouldn't know about that, but almost any stew or sauce can benefit from some nutritional yeast, unless it has a very delicate or clashing taste (say if you're making something japanese, or sweet.)
it usually works best blended into something liquidy, so you can try adding it to melted margarine or oil with other flavours for a spread, or use it for a "caesar" style dressing.
i make a lot of vegan risotto and polenta and think nutritional yeast (sometimes with a pea-sized pinch of miso) tastes better in those than store bought fake parmesan.
it's also a great coating for tofu or anything else you want to bread, like vegatables, gluten, etc... if you want a thin, crispy flour coating,
start by marinating the tofu for at least some minutes in soy sauce, broth, or anything you'd like mixed with a bit of nutritional yeast for thickening.
make a mix of 1 part nutritional yeast, 2 parts flour (whole wheat or non wheat work well) with spices of choice and dredge the tofu in it, making sure it's all covered, then straight to the pan or oiled baking sheet.
if you want the tofu breaded or otherwise-crusted, double the amount of flour/n.yeast mixture and blend half of it with warm water in a separate bowl until it's somewhere between water and raw egg in thickness (sorry for the gross imagery.)
start by coating the marinated tofu in the dry flour/n.yeast mixture, continue to quickly dip it in the wet mixture, then coat it with the crumb mixture.
it sounds complicated but it's a fairly quick process and ensures superb breading results.
(the nutritional yeast will lend a very nice taste to the coated tofu and adheres to it well, but the technique i just described should work well with just flour and spices too.)
