Toss the beef with the flour. Season with salt and pepper and half the ground thyme.
Sear the meat in the hot skillet. Remove to the slow cooker.
Add the butter to your skillet and cook the onions until translucent. Season with salt and pepper. Add the garlic and cook 1 to 2 minutes more.
Add the red wine to the skillet. Because the slow cooker is sealed, the alcohol doesn’t burn off as much. The liquid also helps get any of those delicious brown bits off the bottom of your pan. Simmer and let the wine reduce by a third.
Add the beef stock, tomato sauce and Worcestershire sauce and bring back up to a simmer.
Stir in the tomato paste and the remaining thyme. Cook 1-2 minutes more while the sauce thickens.
Layer the potatoes on top of the meat, then add the carrots on top of the potatoes.
Pour the mixture into the skillet over all the ingredients in the slow cooker..
Set the slow cooker to LOW for 8 hours.
Garnish with fresh parsley, if desired before serving.