Remove flesh from sweet potato, discard skin and mash in a large bowl.
Add turkey, egg, dried onion, 1/4 cup ketchup, marjoram and 1 teaspoon kosher salt, and mix with the ground turkey using a fork until mixed well.
In a small bowl combine 2 tablespoons of the ketchup with Worcestershire sauce.
Shape into a loaf and place on a baking sheet. Spoon sauce on top.
Bake uncovered for 55 minutes, remove from oven and let it sit for 5 minutes before slicing.
Notes
*If you don't have leftover baked sweet potatoes, you can bake the sweet potato in the oven, or air fryer, but for this recipe it’s quickest to do it in the microwave.To microwave sweet potato, pierce the potato several times with a fork, and wrap in a paper towel. Microwave 4 - 6 minutes, or until it is soft to the touch, adding more time if needed.