Source: http://www.onceuponachef.com/2012/03/guinness-lamb-stew-with-vegetables.html
Season the meat with salt and pepper and then brown it in batches in a large pot or Dutch oven.
Be sure the oil is very hot and don’t crowd the pan or the meat won’t sear properly. This step is a bit time consuming but important because it caramelizes the surface of the meat and adds wonderful depth of flavor to the stew.
Set the meat aside, then add the onions and garlic to the pot, along with a few tablespoons of water to loosen the brown bits from the bottom of the pan.
Stir in the tomato paste and cook a few minutes more.
Add the lamb back to the pot and sprinkle it with flour, which will thicken the broth as it cooks.
Cook and stir for for a few minutes until the flour dissolves.
Add the braising liquid, which is simply beef broth, Guinness, water and herbs.
Bring the broth to a boil, then cover and simmer for about an hour and twenty minutes.
Add the carrots and potatoes and continue cooking until the meat is tender and the vegetables are cooked, about 30 minutes more. Be sure to stir it a few times so the vegetables don’t stick to the bottom of the pan.
As you can see below, the broth thickens up nicely as it continues to cook. Right before serving, stir in the frozen green peas. They’ll defrost and cook right in the stew.
You can definitely make this stew a day or two ahead, as the flavor only improves. Just note that the broth thickens up quite a bit in the fridge so you may need to add some water to thin it out.
