Prepare your potatoes by washing and peeling if desired and place in the bottom of the Instant Pot. Pour over the broth and add the trivet to the top of the potatoes.
In a large mixing bowl, add the ground beef, onion, breadcrumbs, ½ cup of ketchup, garlic salt, pepper, eggs, and Worcestershire sauce. Mix well until everything is combined. (I find the easiest way is to use your hands)
Place the meat mixture on a piece of aluminum foil and shape into a loaf. Fold the aluminum foil so that it makes a “bowl” to catch any drippings.
Place the meatloaf on the trivet and make sure the aluminum foil is still in place so that there is no leaking onto the potatoes.
Place the lid on sealing and set the Instant Pot on high pressure for 25 minutes. Manually release any pressure after the timer goes off. To make sure the meatloaf is completely cooked through, use a kitchen thermometer to test the temperature of the inside. It should be at least 160 degrees F.)
CAREFULLY remove the trivet with the meatloaf and place on a baking sheet. Top with ½-3/4 cup ketchup and spread evenly. Place the baking sheet under the broiler in your oven for 3-4 minutes until caramelized. Watch carefully because the top with burn fast.
Remove any excess broth from the potatoes (if desired) and add in the butter, garlic salt, and half and half and mix using an electric mixer (or you can also just use a wire masher).
Serve and enjoy!