A concoction made of
tempeh,
tofu, or
seitan that is
smoky and
salty like real
pork bacon.
A good recipe is to fry one of the above meat analogs until they're crispy then to make a mixture of soy sauce, nutritional yeast, and liquid smoke that tastes like bacon to you, and throw it in and coat the strips of fried stuff, and serve hot and crispy. It won't make you think you're eating bacon, but it might taste good.
There are also store-bought veggie bacons, if you shop at the right stores.