Season the meat with salt and pepper and dredge in flour. Be sure to shake off any excess flour. If you don't, the flour can burn and will make a mess on the bottom of the pan. Just a light dusting is fine.
Heat 1 tablespoon of oil in a preheated fry pan over medium high heat. When it starts to shimmer but is not smoking, add the meat and brown all sides. Don't let the meat touch, so if your pan isn't big enough, brown in batches. The best tool for turning the meat is a pair of kitchen tongs, one of the most important tools in your kitchen. When the meat is browned, transfer it to the crock-pot.
Saute the onions in the same pan. Reduce the heat to medium, add the remaining tablespoon of oil and then the onions. This is a good time to season with a little salt but not too much. Cook the onions until deep golden brown, being sure to stir frequently so they don't burn.
Add ½ cup stock to deglaze the pan, scraping the bottom with a wooden spoon to loosen any of the brown bits (fond) stuck to the bottom of it. Add the fresh thyme. Add the onions and the deglazing liquid to the crock pot.
Add the sliced carrots and mushrooms to the crock pot along with the remaining 2 cups of stock, cover and set to low. I have read it helps to first place a layer of aluminum foil over the top of the crock pot and then the cover. Not sure if this helps but sometimes I make the effort.
Cook on the low setting for about 5 hours or until the meat is tender.
Many recipes I read say to spoon off any fat that accumulates at the top. I have never found this easy to do but I know it is worth a try. Sometimes I make a stew the day before so I can let the fat rise to the top and congeal when refrigerated. Then all I have to do is spoon out the layer of congealed fat. Enough about fat.
Add the parsley to the pot, stir and adjust seasonings with salt and pepper.
If the sauce is too thin, you can always make a quick thickener with a little flour or cornstarch mixed with water (a slurry) and add it to the pot. The only problem with this is that, if you don't bring the starch up to a boil, your sauce can taste a little, well, starchy. So, if you do find you have to thicken the sauce, you might have to turn the crock pot to high for a little while to cook off any starchy taste.