Mix ground turkey, green onions, feta cheese, basil, and Worcestershire sauce together in a bowl. Divide turkey mixture between 6 muffin cups.
Bake in the preheated oven until no longer pink in the center, 15 to 20 minutes. An instant-read thermometer inserted into the center should read at least 165 degrees F (74 degrees C).
While the meatloaves bake, heat balsamic vinegar in a small saucepan over medium-low heat; cook, stirring regularly, until reduced to a syrup-consistency, 10 to 15 minutes. Drizzle balsamic reduction over the loaves.
