Step 1: Prepare the Beef

1. Pat the beef chunks dry with a paper towel to remove excess moisture. This ensures they brown properly.
2. In a bowl, toss the beef with flour, salt, and black pepper until evenly coated.

Step 2: Sear the Beef

1. Heat the olive oil in a large Dutch oven or heavy-bottomed pot over medium-high heat.
2. Add the beef in batches, ensuring not to overcrowd the pan, and sear on all sides until browned. This step locks in flavor. Remove the beef and set aside on a plate.

Step 3: Sauté the Vegetables

1. In the same pot, add the diced onion and cook for 3-4 minutes until softened.
2. Add the garlic and cook for another minute, stirring frequently to prevent burning.

Step 4: Build the Stew Base

1. Stir in the tomato paste and cook for 1-2 minutes to deepen its flavor.
2. Pour in the Guinness stout, scraping the bottom of the pot with a wooden spoon to deglaze and release any browned bits.
3. Add the beef broth, Worcestershire sauce, thyme, and bay leaf, stirring to combine.

Step 5: Add the Meat and Vegetables

1. Return the seared beef to the pot along with the carrots, potatoes, and parsnip (if using). Stir to ensure everything is evenly coated in the liquid.

Step 6: Simmer the Stew

1. Bring the mixture to a gentle boil, then reduce the heat to low. Cover the pot and let it simmer for 2 hours, stirring occasionally.
2. After 2 hours, check the beef for tenderness. If not fully tender, continue cooking for another 20-30 minutes.

Step 7: Add the Peas and Finish

1. Stir in the frozen peas and cook for an additional 5-10 minutes. Adjust the seasoning with more salt and pepper if needed.

Step 8: Serve and Garnish

1. Ladle the stew into bowls and garnish with fresh parsley. Serve warm with mashed potatoes, crusty bread, or your favorite side.