Mix together all meatball ingredients until well combined.
Roll into 1" balls (a cookie scoop works great)
Press the "saute" function on the Instant Pot. Once it is hot, spray the bottom of the Instant pot with cooking spray and place meatballs in about 1//2" apart (you will probably have to do this in 2-3 batches depending on the size of your Instant Pot).
Saute meatballs for 3-4 minutes, then flip and saute another 3-4 minutes.
Remove meatballs from Instant pot and place on a paper towel.
Add about 1 cup of the beef Consomme to deglaze the pot and scrape up any brown bits with a spatula. Add Worcestershire sauce, and ground mustard and stir well.
Add meatballs back to the pot and set Instant Pot to high pressure for 5 minutes, doing a quick release when finished.
Remove meatballs from the Instant Pot and return setting to "saute". Add remaining beef Consomme and heavy cream and bring to a simmer.
If you want to make the sauce even thicker, combine cornstarch and water in a small bowl to form a slurry. Slowly whisk the mixture into the Instant Pot until you reach your desired consistency (you may not need all of the mixture).
Add salt and pepper to taste, if needed.
When thickened, return the meatballs to the Instant Pot and stir into the sauce.
Serve over egg noodles, mashed potatoes, or rice.