Start by heating the olive oil in a skillet over medium-high heat. Sprinkle your beef bites with salt and pepper, then sear them in the skillet until nicely browned on all sides. This should take about 3-4 minutes. You might have to work in batches to avoid crowding the pan. Once browned, transfer the beef to the slow cooker.
Toss the halved new potatoes and sliced onion into the slow cooker with the beef.
In a bowl, combine the garlic, beef broth, balsamic vinegar, soy sauce, and brown sugar. Stir until the brown sugar is dissolved, then pour the mixture over the beef and potatoes in the cooker.
Cover and set the slow cooker to LOW for 6-8 hours, or HIGH for 3-4 hours, or until the beef is tender and the potatoes are cooked through.
In the last half hour of cooking, stir in the cornstarch mixture to thicken the sauce.
Once done, give the dish a gentle stir to combine everything, being careful not to break the potatoes. Sprinkle with fresh parsley for a pop of color and added freshness.
