Start by preparing your produce. Dice beef, carrots and potatoes into large chunks. Make sure that the vegetables are bigger than you normally would chop them, or they will cook too fast and go mushy.
Dice the onion and celery.
Heat up a little oil in a skillet or frying pan on medium heat, and add diced beef. Cook until the surface of the beef chunks has browned on all sides, then transfer the beef to your slow cooker, including any liquid left in the pan.
Heat up another spoon of oil in the same skillet, and add your onion. Sauté for a few minuted until the onion is soft and translucent, then add the garlic. Sauté for another minute, then add the onion to the slow cooker.
Add the carrots, potatoes, dried parsley, dried thyme, beef stock, bay leaf and celery to the slow cooker. Stir to combine the ingredients. Cover with a lid, and slow cook for 4-6 hours on high, or 6-8 hours on low.
About 30-40 minutes before you want to serve the stew, it’s time to thicken up the broth. In a small jar, combine the cornstarch with the water. Stir until the mixture is completely smooth, then pour into the stew and stir. Cover with a lid, and leave the slow cooker on for another 30 minutes.
The broth should now have thickened up nicely. If you prefer a really thick stew, you can use an extra tablespoon of cornstarch.