Position a rack in the upper third of the oven and preheat to 425 degrees F. Line a rimmed baking sheet with aluminum foil or parchment.
Heat the olive oil in a medium skillet over medium heat. Add the onion and bell pepper and cook, stirring occasionally, until the onion is translucent and the pepper is softened, 5 to 6 minutes. Season with salt and black pepper. Remove from the heat.
Add the Worcestershire, tomato paste and 2 tablespoons of the harissa to the onions and peppers; stir to combine.
Beat the eggs in a large bowl. Add the breadcrumbs, milk, garlic powder and 1/2 cup of the parsley and whisk to combine. Add the onion and pepper mixture and stir to combine. Add the turkey and season with salt and black pepper. Lightly fluff the mixture with a fork until well combined.
Divide the meatloaf mixture into 4 equal mounds. Transfer to the prepared baking sheet and form each mound into an individual meatloaf with your hands.
Stir to combine the ketchup with the remaining 2 tablespoons harissa in a small bowl. Spoon over each loaf and spread to coat the tops. It will look like a lot of glaze but, don't worry, it's the right amount.
Bake on the upper oven rack until the internal temperature reaches 165 degrees F, 20 to 25 minutes.
Sprinkle the meatloaves with the remaining parsley and enjoy.