In a medium bowl, combine the ground turkey, minced onion, olive oil, chopped sundried tomatoes, crumbled feta cheese, breadcrumbs, egg, marjoram, salt, and pepper. Mix everything until just combined, being careful not to overmix, which can lead to a dense meatloaf.
1 ½ pounds ground turkey, ½ small onion, 1 tablespoon olive oil, ½ cup sundried tomatoes, ½ cup feta cheese, ½ cup breadcrumbs, 1 large egg, 1 teaspoon marjoram, Salt and pepper