Remove stewing beef from fridge, sprinkle with salt and pepper. Allow beef to come to room temperature, about 20 minutes.
Heat cast iron pan to medium high heat. Once hot add vegetable oil. When oil shimmers add beef and brown 1-2 minutes per side. Do it in batches and set beef aside.
Turn heat down to medium, add onion and sauté for 2 minutes. Add bacon and cook 3 minutes more. Add garlic and cook 45 seconds or until you can smell garlic.
Add beef back to pan. Add two cups of red wine, use spatula to pick up bits sticking to bottom of pan. Bring wine to a boil and let it cook until wine is reduced by half.
Move everything to slow cooker or dutch oven, except for potatoes and corn starch. Add fresh thyme sprigs. Cook on low for 3 hours in slow cooker or at 190F in oven with top on.
At 3 hour mark add potatoes, ensuring they are submerged in liquid.
At 3 1/2 hour mark take a cup of the stew liquid and add a tablespoon of corn starch to it. Mix thoroughly and to stew.
Serve after 4 hours, removing thyme sprigs.
