Sprinkle beef pieces fairly generously with kosher salt and freshly ground black pepper.

Heat large heavy pot over medium-high heat. When hot, add 1 tablespoon of the oil, swirling it around bottom of pot. When oil is shimmering, carefully add beef pieces, leaving at least 1/2" space between pieces. Crowding the beef will cause it to steam rather than brown, so this step will need to be done in batches. Sauté beef until deeply browned on two sides, about 5 minutes per batch. Remove beef to a plate after each batch is browned, adding another tablespoon of oil to the pot prior to adding more beef. When the final batch is browned, add all browned beef back to the pot, along with any accumulated juices from the plate. Add beef broth, Guinness, red wine, tomato paste, sugar, thyme, Worcestershire sauce, soy sauce, and bay leaves. Stir to combine. Bring mixture to a boil. Reduce heat to medium-low, then cover and just barely simmer for 1 hour, stirring occasionally.

While stew is simmering, prepare potatoes, onion, carrots, and garlic. Heat a large skillet over medium heat. Add butter; melt. Add potatoes, onion, and carrots. Sauté until onions are softened, about 15 to 20 minutes. Stir in garlic and sauté for two minutes more. Remove from heat.

Add sautéed vegetables to stew and simmer uncovered for another 45 minutes. Potatoes and beef should be very tender. If the beef isn't fork-tender, continue to simmer until it is. Taste test and add a bit more salt and pepper, if needed. Discard bay leaves. Spoon off any obvious fat from top of stew. Serve hot in individual bowls, with fresh parsley sprinkled over the top.

This stew can be prepared a day or two prior to serving - just refrigerate in the meantime, and bring to a simmer prior to serving.

This stew also freezes well.