In a large Dutch oven, cook the bacon over medium-high until crisp, 4 minutes. Using a slotted spoon, transfer to a bowl. Season the beef with salt and pepper and add it to the pot in a single layer. Cook, stirring, until browned all over, about 8 minutes. Transfer to a plate. Add the mushrooms and cook, stirring occasionally, until browned, about 4 minutes.
Reduce the heat to medium and stir in the cooked meat, carrots, onion, tomato paste and butter. Season and cook, stirring, 1 minute. Sprinkle with flour and cook, stirring, 2 minutes. Stir in the stock, wine and 1 tbsp. thyme; bring to a boil. Reduce the heat to medium-low, cover and simmer until the meat is tender and the sauce 1 thickens, about 1 1/2 hours.
Stir in the cooked bacon; season. Divide among bowls, garnish with the remaining thyme and serve with the baguette slices.