In a large Dutch Oven or pot, over medium-high heat, heat the oil. Add the diced bacon and cook until crispy, about 4-5 minutes. Remove it with a slotted spoon and set aside while leaving some fat in the pot.
Season the beef generously with salt and pepper before adding it to the pot in batches. Brown each piece on all sides, about 1-2 minutes per side, then remove them from the pot and reserve alongside the bacon.
Lower the heat to medium, adding more oil if necessary before stirring in sliced onions. Sauté until they begin to brown, approximately 5 minutes, then add minced garlic and cook until fragrant.
Mix in flour and tomato paste until well combined, cooking for another minute or two until everything turns a deep red color. Pour in both types of broth while scraping any browned bits from the bottom of the pot.
Add back in your reserved beef and bacon along with thyme sprigs, brown sugar, Worcestershire sauce, salt, and pepper to taste before bringing everything to a boil.
Once boiling, cover your pot and reduce heat to simmer for about one hour before adding carrots and potatoes; cover again until everything is tender—approximately one more hour of cooking time will do!