Heat oil in a large pot or Dutch oven over medium-high heat. Pat beef dry, then brown in batches until nicely seared on all sides. Remove beef and set aside.

Add diced onion (and celery, if using) to the pot and sauté until softened, about 5 minutes.

Sprinkle flour over the onions and stir well to coat. Cook for 1-2 minutes to remove raw flour taste.

Gradually stir in beef broth, scraping browned bits from the pot bottom.

Return beef to the pot. Add salt, pepper, and garlic powder.

Bring to a boil, reduce heat to low, cover, and simmer for 1.5 hours, stirring occasionally.

Add potatoes and carrots (and peas, if using). Continue simmering, covered, for another 30-45 minutes or until beef and vegetables are tender.

Taste and adjust seasoning before serving.