Begin by mixing all of the meatball ingredients together in a mixing bowl until they are combined. Use a spoon or meatball scooper to portion out about 30 meatballs and set them aside on a piece of parchment paper. When the meatballs are all portioned, turn the Instant pot to Saute and place half the butter in the pot. When the butter is melted, add half the meatballs and cook for 4-5 minutes or until golden and crispy on each side. Repeat with the other half of the meatballs until all of them are cooked.
Next up, deglaze the pot by adding in the beef consomme and stir to get all the crispy bits off the bottom. Then add in the remaining butter, mustard, Worcestershire, and half of the heavy cream. Stir until combined, then turn off the Instant Pot.
Add the meatballs into the Instant Pot, close the lid, and set the steam release valve to the "sealed" position. Set the pressure cooker on Manual for 4 minutes. When the Instant Pot is done, allow it to release naturally for 6 minutes. While the meatballs are cooking, whisk the flour into the remaining cream. When the meatballs are done, do a quick release and move the meatballs to an oven-safe dish with a lid.
Next, set the Instant Pot to saute once more and bring the sauce to a simmer. When the sauce begins to bubble, whisk in the cream mixture and allow to cook for a few minutes so that it thickens. Cancel the saute and allow the sauce to cool slightly before seasoning with salt and pepper. Add the meatballs back in and give a good stir before serving!