Cut the stewing beef into chunks and season with salt and black pepper.
Heat 1 to 2 tablespoons oil in a large pot or Dutch oven over medium-high heat. Add the beef and brown on the outside, working in batches if needed.
Add the chopped onions to the pot and cook for a few minutes, scraping up the browned bits from the bottom.
Stir in the red bell pepper, chopped tomatoes, and minced garlic. Cook until the tomatoes begin to soften.
Add the sweet paprika, cumin, dried thyme, tomato paste, salt, and black pepper. Stir and cook for 1 to 2 minutes.
Return the beef to the pot. Add the red wine, if using, then pour in the beef stock, chicken stock, or water.
Add the bay leaves, bring to a simmer, cover, and cook gently for about 1 hour to 1 hour 15 minutes.
Add the celery, carrots, and potatoes. Continue simmering for 30 to 40 minutes, or until the beef is tender and the vegetables are cooked through.
Remove the bay leaves. Taste and adjust salt and pepper, then let the stew rest for 10 minutes before serving.