Prep the Beef: Pat dry beef with paper towel; sear in batches in the hot oil. Season the beef generously with salt and pepper. Heat a large Dutch oven or heavy-bottomed pot over medium-high heat. Add a drizzle of oil and sear the beef in batches, making sure not to overcrowd the pan. Sear each piece until golden brown on all sides. Transfer to a plate and set aside. Preheat oven to 350.

Sauté the Veggies: In the same pot, lower the heat slightly and add diced onions and carrots. Cook until softened, about 5 minutes. Stir in the garlic and cook for another minute until fragrant. Return the seared beef to the pot.

Build the Sauce: Sprinkle flour over the veggies and beef, stirring constantly to coat. Cook for 2-3 minutes to remove the raw flour taste. Slowly pour in the red wine, scraping up any browned bits from the bottom of the pot.

Simmer the Stew: Add the water and beef bouillon to the pot, stirring until combined. Add tomato paste, along with the pearl onions, thyme and bay leaves, and mix well. Bring to a boil, then reduce the heat to low. Cover with a lid and place in the oven for 2-3 hours.

Check for Doneness: The beef should be fork-tender, and the sauce should be rich and glossy. Taste and adjust seasoning with salt and pepper as needed. You shouldn't need to do anything once it comes out of the oven, however, if the sauce is too thin, you can drain the sauce into a new pot, reduce it down, and possibly even add a cornstarch slurry, if needed. But I never need to do this; it's always perfect right when it comes out of the oven!

Serve and Garnish: Ladle the Beef Bourguignon into bowls over mashed potatoes and sprinkle with fresh parsley.