Tempeh is a firm, chewy cake made from fermented soybeans, and its dense texture makes it a hearty yet cholesterol-free and very low-fat stand-in for meat. It’s a staple of vegan cuisine. You can crumble into chili, or slice it and throw it on the grill. Here, we use it as a substitute for beef in fajitas. Tempeh does well marinated (it really soaks up the flavors). For this weeknight-friendly recipe, combine the tempeh with the marinade in the morning, pop it in the fridge, and then finish the recipe in the evening. We use plain old soy tempeh, but you can use other varieties, such as flax or three-grain. Serve with salsa (either End-of-Summer Pico de Gallo or Fiery-Sweet Peach Salsa) and a dollop of Guatemalan Guacamole.