Step 1

Preheat the oven to 350°F with a rack in the center position.

Step 2

Season the beef all over with 2½ teaspoons of the salt and pepper.

Step 3

Place the bacon in a Dutch oven or heavy-bottomed pot set over medium-low heat. Cook, stirring occasionally, until the bacon crisps and the fat is rendered, about 10 minutes. Using a slotted spoon, transfer the bacon to a paper towel–lined plate, reserving the fat in the pan.

Step 4

Increase the heat to medium-high. Once the fat is just smoking, working in batches, add the beef in a single layer and cook until browned and crisp on all sides, 10 to 15 minutes. Transfer to a plate and continue with the remaining beef.

Step 5

Reduce the heat to medium-low, add the yellow onion and carrot and cook, stirring occasionally, until softened, about 10 minutes. Stir in the garlic, tomato paste, bay leaf, and 1 sprig of thyme and cook until fragrant, about 1 minute more. Add in the flour and cook, stirring constantly, for about 1 minute, or until mostly incorporated with the fat.

Step 6

Increase the heat to medium-high, pour in the wine and cook, scraping up any browned bits from the bottom, until simmering, 5 minutes. Stir in 3 teaspoons of the bouillon and 1 cup of water and bring to a simmer over high. Return the bacon and beef, along with any collected juices, to the pot. Cover and roast in the oven until the beef is very tender, about 2½ hours.

Step 7

Meanwhile, heat the olive oil in a large skillet over medium-high heat. Once the oil is just smoking, add the mushrooms and pearl onions and season with the remaining ½ teaspoon of the salt. Cook, undisturbed, until the mushrooms and onions are browned, about 5 minutes. Add ½ cup of water, the remaining sprig of thyme and the remaining teaspoon of bouillon. Bring to a boil over high heat, then reduce the heat to a simmer, cover and cook until the onions are tender, about 10-12 minutes. Uncover, increase the heat to high, and cook, stirring frequently, until the vegetables are caramelized, 2 to 5 minutes more.

Step 8

Serve the Beef Bourguignon, pearl onions and mushrooms over mashed potatoes, if using, then sprinkle with parsley.