Start by gathering all the necessary ingredients.
In a spacious bowl, gently combine the ground turkey, eggs, finely chopped onion, pressed garlic, breadcrumbs, ketchup, milk, Worcestershire sauce, salt, sage, poultry seasoning, and pepper. Mix until all the ingredients are thoroughly blended.
Line a 7-x 3-inch round pan with foil and transfer the meatloaf mixture onto the foil. Alternatively, shape the meatloaf on a large sheet of heavy-duty foil. In the Instant Pot, add 1 1/2 cups of water. Place the pan with the meatloaf onto the trivet and lower it into the Instant Pot.
Secure the lid in place and ensure the knob (on some models) is set to the sealing position. Choose the pressure cook or manual (high pressure) setting and set the timer for 35 minutes.
After the timer goes off, allow the pressure to naturally release for 10 minutes, and then perform a careful quick release. Insert an instant-read thermometer into the center of the loaf to check the temperature. For ground turkey, the minimum safe temperature is 165°F. Move the meatloaf to a rack.
While the meatloaf rests, prepare the tantalizing topping. In a small bowl, combine the ketchup, brown sugar, and Dijon mustard. Stir until it's smooth and well-mixed.
Turn on the oven broiler and generously spread the topping over the meatloaf. Broil it until the topping is hot and begins to bubble.Note: If using the oven isn't an option, heat the topping mixture in a small saucepan and spoon it over the meatloaf. Transfer the meatloaf to a serving dish, and for a touch of finesse, garnish it with chopped parsley, if desired. Slice and savor the flavor!