Prepare the Beef:
In a large bowl, combine flour, garlic powder, salt, and black pepper.
Add the cubed stewing beef to the bowl and toss it until well-coated with the flour mixture.
Brown the Beef:
Heat 3 tablespoons of olive oil in a large pot or Dutch oven over medium-high heat.
Add the beef in batches, making sure to brown it on all sides (about 5-7 minutes per batch). Once browned, remove the beef and set it aside.
Sauté the Onion:
In the same pot, add the chopped onion and cook for 3-4 minutes until it becomes soft and translucent.
Stir in the tomato paste and cook for another minute, allowing the flavors to meld.
Deglaze the Pot with Red Wine (Optional):
Pour in ½ cup red wine (if using) to deglaze the pot, scraping up any brown bits from the bottom of the pot. Let the wine cook for 3-5 minutes to reduce by half.
Simmer the Stew:
Return the browned beef to the pot and add 6 cups beef broth, cubed potatoes, carrots, celery, and rosemary.
Bring the stew to a boil, then reduce the heat to low. Cover and let the stew simmer for 1.5 to 2 hours, or until the beef is tender and the vegetables are fully cooked.
Thicken the Stew (Optional):
To thicken the stew, mix 2 tablespoons cornstarch with 2 tablespoons water to form a slurry.
Stir the slurry into the stew and cook for an additional 5-10 minutes, or until the stew reaches your desired thickness.
Add Peas:
Stir in the ¾ cup peas and cook for another 5 minutes, just until heated through.
Taste and Adjust Seasoning:
Taste the stew and adjust the seasoning with extra salt and pepper if needed.
Serve and Enjoy: