Heat the cooked meatballs in a pan with a very little bit of oil and cook over medium heat until they are heated on the outside.
Add the flour and continue the recipe as is from there.
For Beef and Guinness® Stew in the slow cooker
Brown the beef on the stovetop in a large skillet.
Follow the recipe instructions until the point where the stew needs to simmer.
Transfer the stew to a slow cooker and cook it on low for 3-4 hours.
Be mindful of how hot your slow cooker cooks since they all heat differently. Larger volume slow cookers will cook the same amount of food much faster than a smaller volume slow cooker.For Beef and Guinness® Stew in the Instant PotYou should never add flour or other thickeners before the pressure cooking cycle since it can cause food to stick to the bottom of the pot and burn. The pressure cooker needs the thinner liquid to create the steam that forces the pot to go under pressure.
Put the 1 Tbsp. oil in the inner pot and brown the meat in it without the flour (you can put the cayenne, salt, and pepper on it) on sauté mode.
Add the beer (up to the amount recommended for liquid on your model of pressure cooker), onions, garlic, thyme, and carrots to the pot.
Cook on manual pressure (high if you have the option) for 25 minutes.
NPR for 15 minutes, then release pressure and open lid.
Mix the flour with about ½ cup of the liquid from the pot (careful, it's hot!), whisking well to get any lumps out.
Add the flour mixture back to the pot and stir gently to mix.
Add the tomato paste and the remaining beer and heat on sauté mode for just long enough to heat through (watch carefully for burning - this won't take long).
Turn off the Instant Pot as soon as the stew is hot and serve the stew over mashed potatoes.