Pat the boneless beef chuck roast dry with a paper towel. Season with kosher salt, black pepper, garlic powder, onion powder, and smoked paprika. Season both sides.
Heat olive oil in a pan. Brown chuck roast on both sides - roughly 4-5 minutes per side. Once browned, add chuck roast to your slow cooker.
On top of chuck roast, add the celery, baby carrots, onions, red skinned potatoes, thyme, rosemary, and beef broth. Add the wine, as well, if you so choose. Stir.
Cook on low heat for roughly 8 hours. You will want your beef to reach an internal temperature of, at minimum, 145F. I usually cook mine to 155F-160F.
Serve roast and vegetables topped with gravy/sauce; garnish with parsley, if desired.
For Thickening Sauce
If you want your sauce to be thicker, similar to gravy, remove roast and vegetables from the slow cooker. Strain the liquid into a saucepan. Mix together corn starch and water and pour into the liquid. Whisk constantly for 2-3 minutes, or until the mixture has reached your desired consistency.
Notes
Don't skip the browning - it makes all of the difference!
Thicken the sauce with a cornstarch mixture; see below.
To add additional depth to the flavor, add 1/2 - 1 cup of dry red wine.
Cut your vegetables very thick/rough -- they will be cooking for a significant amount of time. i.e.: thick baby carrots, thickly-sliced onion, thickly-sliced celery.
Cook on low -- I find that this is the optimal way!
Don't serve anything else with this dish; it's a balanced home run in and of itself.