Cut the meat into 2 inch pieces and season to taste with kosher salt and fresh ground black pepper (make sure to get as much coverage as possible)
Heat oil in a large, heavy bottomed pot over high heat - Add seasoned meat in batches and brown well all over - Using a slotted spoon, remove browned meat to a plate and set aside until needed
Lower heat to medium -Add garlic and onion - Sauté until onion is soft and translucent (apx 3-5 minutes) -Add bacon and continue to sauté until bacon is browned and slightly crisp (apx 5-8 minutes)
While continuously stirring, slowly sprinkle in the flour until well integrated
Add Guinness™ and give everything a good mix (be sure to gently scrape the bottom of the pot with spatula to bring up all of the 'fond') - Add all of the remaining ingredients (minus potatoes if using) and the browned meat (including any juices) to the mixture - Thoroughly combine
Add enough water so meat and veggies are just submerged
Cover pot and bring to a gentle simmer - Allow to cook covered for 2 hours (adjust heat as necessary)
After 2 hours, add the potatoes and remove the lid - Continue to simmer for an additional 30 minutes to an hour until potatoes are cooked through, meat is 'fall apart tender' and sauce has thickened to desired consistency (remember: this is a stew so it should be pretty thick - think a slightly thin gravy)
Adjust seasoning with kosher salt and fresh ground pepper to taste - Remove bay leaves and thyme sprigs
Serve hot with smashed potatoes, Irish soda bread or a good 'hunk' of crusty bread, and a cold Guinness™ Draught