I'm not a huge fan of the slow simmered meat gravies, I think they become greasy too easily. To make gravy quickly here's what you need to do...
Saute one 1/2 an onion with about a tbsp of olive oil
Add 1 hamburger patty ( I usually have some of these seasoned and ready to go)
Break up the burger with the back of a wooden spoon and stir until it is fully cooked
sprinkle with some garlic powder and a little dried italian seasoning (oregano, basil, rosemary, parsley)
Use fresh herbs if you have 'em.
Add one can of crushed-peeled tomatos
add 1/2 half can of water (rinse out the tomato can with it)
a dollop of red wine (optional)
Let it cook for about 15 min. The rest is gravy....
The good people at Sclafani will sell you some tomatoes for 2.29 a can (plus shipping- which might be pricey). But if you live in say, Arkansas- well worth it.