This sweet-and-sour stir-fry, featuring high-protein seitan or tempeh along with colorful vegetables and pineapple, has several steps but can be made easily and at a leisurely pace. Best of all, it results in a delicious and nourishing meal. This is especially good served over bean-thread noodles or Asian brown rice vermicelli, but soba or udon work well, too. Long-grain brown rice and brown basmati rice are good choices as well.