Cut the beef into cubes and pat dry with a paper towel.
Add olive oil to the Dutch oven and turn heat on to high while you sear the meat. Add the meat to bottom in batches. Don't overcrowd the pot or the meat will steam and not sear. Use tongs and work in batches, removing seared pieces to a plate as you work. Sear all sides of all the meat until it's all browned to perfection. Transfer all the meat to the plate while you cook the onions.
Add the onions to the pan and cook over medium high heat until they begin to turn amber in colour. Then add the garlic and cook for one minute longer. Add the meat back into the pot and stir well.
Toss the flour, salt and pepper into the pot and stir until the flour coats all the meat evenly. This should only take about 1 to 2 minutes.
Add the tomato paste to the bottom of the Dutch oven and stir until it incorporates well.
Then, pour the Guinness into the Dutch oven and use a wooden spoon to loosen any brown bits on the bottom of the pan. That will add so much flavour to your stew.
Add the beef stock and bay leaves but not the veggies yet. Bring everything to a boil then cover and simmer for 30 minutes
Uncover the pot carefully and add the carrots and potatoes. Place the lid back on and continue to simmer for another 1 1/2 hours. It's done when the veggies are soft but not mushy.
Remove lid and simmer for another 30 minutes. This will allow the stew to thicken a bit more. If you like yours thinner in consistency you can skip this step.
Pull out the bay leaves and discard them.