Dry the beef: Line a baking sheet with a few sheets of paper towels. Transfer the cubed beef onto the sheet and pat dry with paper towels. Season with salt and pepper on all sides.
Heat 1 tablespoon oil in a large saute pan (I used my cast iron skillet) over medium-high heat. When the oil is sizzling hot, add in the cubed meat (as many as you can without crowding the pan) and cook for 3-4 minutes on each side or until the meat is nicely browned. Continue the same process with the rest of the meat. I had to do it in 3 batches.
Place the seared meat onto a plate and set aside.
To make the soup, place onion, carrots, celery, garlic, potatoes, diced tomatoes (with all its juices), green beans, seared meat, and salt and pepper into the bowl of your slow cooker.
Pout in the beef stock and tomato juice. Give it a gentle stir.
Cook on low for 8-9 hours or on high for 6-7 hours.
Stir in the frozen peas in the last 30 minutes.
Ladle into bowls, garnish with parsley, and serve.