Step 1: Pat beef cubes dry with paper towels and season generously with salt and pepper. Heat 1 tablespoon of olive oil in a large Dutch oven or heavy-bottomed pot over medium-high heat.
Step 2: Sear the beef in batches, ensuring not to overcrowd the pot, until deeply browned on all sides. This browning is crucial for flavor. Remove the seared beef and set aside.
Step 3: Add the remaining 1 tablespoon of olive oil to the pot (if needed). Add the chopped yellow onion and celery and cook until softened, about 5-7 minutes.
Step 4: Stir in the minced garlic and cook for another minute until fragrant. Be careful not to burn the garlic.
Step 5: Pour in the red wine, scraping up all the browned bits (fond) from the bottom of the pot with a wooden spoon. Let the wine simmer for 2-3 minutes, reducing slightly. Stir in the tomato paste and cook for 1 minute.
Step 6: Return the seared beef to the pot. Add the beef broth, Worcestershire sauce, bay leaves, and fresh thyme sprigs. Bring the mixture to a gentle simmer.
Step 7: Reduce the heat to low, cover the pot, and let it cook for 1.5 to 2 hours, or until the beef is very tender.
Step 8: Add the cubed potatoes, carrots, and pearl onions (if using) to the pot. Stir gently to combine. Ensure vegetables are mostly submerged. Cover and continue to simmer for another 45 minutes to 1 hour, or until the vegetables are fork-tender.
Step 9: If you desire a thicker stew, whisk together 2 tablespoons of cornstarch with 2 tablespoons of cold water in a small bowl to create a slurry. Stir the slurry into the simmering stew and cook, stirring constantly, until the stew thickens to your desired consistency.
Step 10: Remove the bay leaves and thyme sprigs. Taste the beef stew recipe and adjust seasoning with salt and pepper as needed. Garnish with fresh chopped parsley before serving.