Cut onions, carrots, celery, and garlic. Set aside. Cut your chuck roast or stew meat into 1–2 inch cubes, trimming away excess fat. Season generously with onion powder, garlic powder, and complete seasoning. Toss the seasoned beef in flour until lightly coated and set aside.
Heat a large skillet over medium heat and add light olive oil. Brown the beef in batches, making sure not to overcrowd the pan. You are not cooking it through. On this step you are only creating a rich crust for flavor. Transfer the browned beef to your crock pot.
Pour the red wine into the hot skillet and scrape up the fond (the cooked bits stuck to the pan) from the bottom of the pan. Allow the wine to reduce for about 30-60 seconds. This will help to concentrate the flavor. If you are serving this recipe to kids or if you do not drink alcohol, no need to worry. The alcohol will cook off in this step. Alternatively, you can substitute with beef broth.
Add butter to the same skillet. Cook the chopped onions until translucent, then add minced garlic and sauté until fragrant. Continue scraping up any remaining brown bits from the bottom of the pan. Transfer everything into the slow cooker.
To the crock pot, add beef broth, carrots, potatoes, celery, Worcestershire sauce, tomato paste, Better Than Beef paste, and your fresh aromatics (thyme, rosemary, and bay leaf). Stir gently to combine. Cover and cook on LOW for 7-8 hours or HIGH for 4-5 hours, until the beef is fork-tender and the broth has developed into a rich, savory stew.
Optional: After slow cooking and before serving, if you prefer a thicker consistency, remove 1/3 cup of broth from the crock pot and mix with 2 tablespoons cornstarch until fully dissolved. Stir the slurry back into the stew and allow it to cook for several more minutes until thickened.
Serve over rice, egg noodles, mashed potatoes, or enjoy it on its own as a hearty, comforting meal.