Place the flour, salt, pepper, and onion powder into a gallon-sized food storage bag. Smush that around in the bag to mix. Add the beef cubes, seal the bag, and shake until the meat is coated.
Place a large skillet over medium-high heat. Pour in the oil and once hot, sear the meat for 1 minute per side until browned. Pour the meat and pan juices into your slow cooker.
Whisk the Worcestershire sauce and cornstarch in a medium bowl until a slurry forms. Whisk in the beef broth, tomato paste, thyme, and oregano. Set aside.
Add the potatoes, carrots, celery, and onion on top of the beef. Then add the beef broth mixture and bay leaves to the slow cooker. Give everything a stir.
Cover and cooker for 4-6 hours on LOW.
Remove the lid and add the frozen peas. Cook for 10 more minutes until the peas are heated through. Sprinkle some chopped parsley on top and serve warm.
Notes
If you want to save some prep time, you can buy the pre-cut stew eat in the meat dept at the store.