Season the beef stewing cubes with salt and pepper.
Heat cooking oil using the saute function of your Instant Pot or Pressure Cooker, then brown the meat on both sides. Set this aside.
Saute onion and garlic until translucent. Deglaze the pot with beef stock, scraping up any bits stuck to the bottom.
Return the beef to the pot then add the potatoes and carrots. Stir to combine.
Add red wine, canned tomatoes, brown sugar, (if using), and tomato paste.
Without stirring, top with beef broth (or stock). Close the pressure cooking lid, place the valve in the sealing position, and pressure cook on high for 35 minutes.
Once the cooking time is over, allow for a 10-minute natural pressure release (NPR).
Mix cornstarch and cold water in a small bowl to make a slurry. Stir this into the stew to thicken. Add the frozen vegetables at this point and stir to combine.
Let cook on the saute function for 5 minutes or until the frozen vegetables are cooked.
Check and adjust the seasoning, ladle into bowls, garnish with chopped parsley, and serve.