Turn on the sauté setting on your Instant Pot and melt two tablespoons of butter inside it. In small batches, brown the beef stew meat, ensuring not to overload the pot. As each batch is browned, transfer it into a separate bowl.
After browning all the meat, melt the remaining two tablespoons of butter in the pot, and add the diced onion.
Sauté the onion until it turns translucent, all while scraping the pot's bottom to detach any browned bits of meat stuck to the bottom. A useful hint here is that browning the stew meat in butter results in a deeply flavorful broth.
Switch off the sauté setting and add the minced garlic into the pot, mixing it well with the cooked onions.
Add the browned beef stew meat with its juices back to the pot, along with the salt, pepper, and bay leaf.
Add four cups of beef stock over the meat and stir the mixture.
Twist the pot lid on and move the steam valve to the sealing position. Press the manual button setting and set the time to 20 minutes.
Once the pressure cooking time has finished, perform a quick release of the steam, then carefully remove the pot lid.
Add the uncooked egg noodles to the pot and stir them in. Pour an additional one or two cups of beef broth to ensure all the noodles are submerged. Replace the lid, close the valve, and push the manual button setting the timer for a 2-minute cooking interval. After this, perform a quick release of the steam before removing the lid.
Check if the noodles are cooked to your preference. If they are, stir the cornstarch slurry until it is fully dissolved, then pour it into the pot.
Press the sauté button and allow the mixture to come to a simmer. As the broth simmers, it will start to thicken. Once it has thickened to your liking, switch off the sauté setting and serve your delicious Instant Pot Beef and Noodles.
Serve in a bowl with some crusty bread and a salad.
Makes 6 to 8 servings.