Use the same pot that the beef was browned in. Remove the pot from the heat to cool slightly. Lower the heat to medium.
Add the garlic to the pot and stir for 15 seconds or until fragrant. Be careful not to burn the garlic.
Add the onions and cook until they soften. Keep stirring.
Add the bacon and cook until they turn brown. Keep stirring.
Add the flour and stir well so that the onions and bacon are coated fairly evenly.
Add the beer and mix well to ensure the flour dissolves.
Add the chicken stock, tomato paste, carrots, celery, bay leaves, and thyme sprigs.
Add back the browned beef and its juices.
Cover the pot with a lid and bring to a boil. Remove any scum that surfaces.
Lower the heat and simmer for 2 hours with the lid on.
Remove the lid and simmer for at least another 30 minutes. The beef should be tender and the sauce thickened slightly.
Remove any excess fat that surfaces.
Remove the bay leaves and thyme sprigs.
Add salt and pepper to taste.