Start by heating up one tablespoon of oil in a large saute or fry pan until hot but not smoking. We're going to brown the beef cubes in stages so start with ⅓ of the beef and brown until all sides are brown. Add the meat to the crock pot. Then add another tablespoon of oil and brown the next batch and then the third.
When all the beef is browned and in the crock pot, deglaze the pan with a little bit of red wine. If you don't want to use red wine, substitute a little of the beef stock. Let the wine cook down to an essence.
Now add the onion and garlic. There should be enough liquid in the pan to saute the onion and garlic but if not, just add a little bit of oil to the pan. When the onion and garlic are lightly browned, add them to the crock-pot.
Next add the carrots and celery to the pan and saute for 5 minutes before adding them to the crock-pot. You could just add the carrots and celery directly to the crock-pot but I like to brown them just a little for an extra layer of flavor.
Add the diced tomatoes, beef stock, bay leaves, Worcestershire sauce, and paprika to the crock-pot and stir to combine all the ingredients. Add a little salt and pepper but you will be adjusting seasoning when the beef stew is almost finished.
Be careful not to add to much salt to the stew if the beef stock is loaded with salt. It's easier to add later and impossible to remove if too much is added.
Let this cook in the crock pot for at least 6 hours or until the beef is tender. Depending on whether you set the crock pot on high or low, the cooking time will vary but in the end you will know it is done when the meat is fork tender.
Taste the sauce and adjust the seasonings with salt and pepper. You can serve this with fresh bread, mashed potatoes, rice, egg noodles or by itself.