In a bag, combine everything listed under “flour mixture for beef”.
In batches, drop pieces of beef into the bag and shake to coat evenly.
In a skillet, place the oil and heat. Drop the pieces of beef in and sear them on all sides, being sure not to overcrowd the pan. You may have to do this batches.
When everything is seared, place the beef into the slow cooker.
Add the remaining ingredients (except cornstarch and water) and cook on low for 5 – 6 hours or until the potatoes are cooked through and the beef is tender.
In the last 30 minutes of cooking, add the slurry of cornstarch, stir, and continue to let cook and thicken.