Step 1

Place the ground beef, breadcrumbs, milk, onion, egg, and salt in a large bowl. Use your hands to gently combine until homogeneous. Shape the meat mixture into a loaf, about 6 inches long and 4 inches wide, and set inside a 6-inch round cake pan; set aside.

Step 2

Combine the potatoes, water, and salt in the Instant Pot insert and stir to combine. Place a trivet over the potatoes.

Step 3

Create a sling for the meatloaf pan by folding a 12-inch long piece of aluminum foil lengthwise into a 3-inch wide strip. Place the meatloaf pan in the center of the strip and then fold up the sides — you should have 3 to 4 inches of overhang (handles) on either side.

Step 4

Lower the meatloaf pan into the Instant Pot and place on top of the trivet. Seal the Instant Pot and set to MANUAL pressure on HIGH for 35 minutes. While the meatloaf cooks, arrange a rack in the middle of the oven and heat to 400°F. Stir the ketchup, brown sugar, and mustard together in a small bowl to make the glaze.

Step 5

When the cook time is over, let the Instant Pot naturally release pressure for 10 minutes. Manually release any remaining pressure. Open the Instant Pot and use the foil sling to carefully remove the meatloaf — there will be quite a bit of fat and juices around the meatloaf, don’t worry if any of this drips into the potatoes. Carefully drain off the fat and juices around the meatloaf. Brush the meatloaf with the glaze and bake until it is glossy and caramelized, 8 to 10 minutes.

Step 6

While the meatloaf bakes, add the half-and-half and butter to the potatoes and mash to desired consistency. Slice the meatloaf and serve with the mashed potatoes.