It's basically a roux made of meat drippings, flour, milk/cream, pepper and often crumbled up sausage. It's a distinctly "Southern cooking" American-ized adaptation. A vegetarian version would just drop out the meat products. A full vegan version may use something like soy or almond milk to...
Keep in mind, our biscuit is more like a soft flaky scone, not a cookie. With a sausage gravy it's delicious.
It's an English cultural thing though. Americans have been coffee drinkers mostly out of spite since George III gave up the colonies.
(I'm teasing).
Yeah, I know, again, I was teasing.