In a large bowl, mix together the ground beef, eggs, breadcrumbs, onion, garlic Worcestershire sauce, 1/3 cup on the ketchup, parsley, salt and pepper with your hands until evenly combined. Place mixture in a disposable loaf pan or form your own out of aluminum foil.
Arrange potatoes in the bottom of the Instant Pot in an even layer. Pour broth or water over the top. Place the wire rack that comes with the Instant Pot over the potatoes. Set meatloaf on top.
Close lid, make sure steam release is set to sealed, and set to manual mode (on high pressure) for 25 minutes. Once done, use quick release to release pressure.
Remove meatloaf using handles on wire rack and drain off any extra liquid. Brush with remaining ketchup and, if desired, place under broiler in oven for 3 minutes to caramelize.
Meanwhile, add heavy cream or half-and-half, sour cream, butter, and salt and pepper to the potatoes in the Instant Pot and mash until creamy. Enjoy!