You can do this with pretty much any meat - pork, venison, drifter - but for purposes of this discussion we're talking about a beef chuck, rump or bottom round roast in the 4 - 5 pound range.
Peel and slice some garlic cloves - as many as you feel like using - lengthwise in half. Pierce the meat on all sides with a thin-bladed knife, and stick half a clove in each cut. Shove them sumbitches in deep.
Rub the meat all over with oil - any neutral-tasting oil like canola or veg will do. Now! Kosher salt and black pepper all over, and it's INTO THE PAN!
That's right, a pan. A nice, heavy-bottmed one. You're going to sear the meat first. (Avoid cast iron if you're going to cook onions in the pan - the acid can react with the iron and taste pooh.) Put the pan over a medium-high flame and let it get nice and hot. When you can't comfortably hold your hand a couple inches from the surface for more than a second or two, you're ready.
Drop the meat in - did it sizzle when it hit the pan? It should sizzle - and sear it on all sides. People used to think this "locked in" the juices. It's been demonstrated to be a bunch of hooey, but I still hear people say it all the time. What it - technically the process is known as the Maillard reaction, athankyouverymuch- does is caramelize the proteins and sugars on the surface of the meat. This results in a tasty brown crust on the meat and - more important - some tasty brown bits in your pan.
Don't sear it too long - this isn't about cooking, it's about a quick caramelization.
Remove the meat from the pan. And for the love of god use tongs. None of this savagery with forks, PLEASE. Okay, lower the heat a bit and throw in a handful or two of onions. White, brown, Spanish, doesn't matter. Sliced, diced, however you like them. They'll release a little of their water and help loosen up the yummy brown crusty things in the pan. Use a wooden spoon to nudge the onions around. Again, you don't need the onions too brown - remember, they'll be cooking a long time in the crock pot. Just start them off. Okay now, drop a couple glugs of wine - red or white, doesn't matter, whatever you happen to be drinking at the moment - into the pan and scrape around the bottom with that wooden spoon.
All right! Kill the burner and turn your attention to the crock pot. Dump a diced rib of celery along with some peeled, roughly chopped carrots, parsnips, and maybe a rutabaga or two into the bottom. Place your browned and baronial cut of beef on top of the root veg with a couple sprigs of thyme, some rosemary, and a couple bay leaves. You like tomatoes? Fine - crush a few plum or Roma tomatoes in your hands and throw them in. Pour the wine and onion mixture from the pan on top. Add more liquid - more wine, or some beef stock, or a mixture of both - until all but the top third or quarter of the roast is submerged.
Are you excited? You should be. 'Cause now it's time to put the lid in place and start the slow cooker. Go HIGH for three to four hours, or (what I recommend) LOW for eight to nine hours. If you opted for less liquid, i.e., more of the meat above the liquid line - you really should go low and slow. And no peeking!
Walk away, take a bath, compose a sonnet, drink, go cop some herb.
When the specified interval has elapsed, turn off the slow cooker and carefully remove the roast to a nice big, deep platter. Tent it with foil and give it about 20 minutes to relax. When you're ready to serve, spread some of the cooked veggies around the roast and spoon some cooking liquid over the top. You can carve, but it should be so tender you can just pull it apart with forks. Mashed potatoes or Yorkshire pudding are great with this. Or just a nice crusty loaf of bread.
You can make a nice thick gravy by straining the cooking liquid and adding it to a roux, like you did for the turkey gravy. But I just like to eat it as is. Whatever you decide, you'll be tucking into the tenderest, most flavorful cheap cut of beef you've ever known.
And maybe use the leftover cooking liquid to make a nice big bowl of egg noodle soup a day or so later.