Preheat the oven to 350°F. Line a rimmed baking sheet with parchment paper or spray it with nonstick cooking spray.
In a medium skillet over medium-low heat, cook the onion, olive oil, salt, pepper, and thyme until the onion is translucent, about 10 minutes. Stir in the Worcestershire sauce, chicken broth, and tomato paste. Mix well and cool to room temperature.
In a large bowl, gently combine the ground turkey, dry stuffing mix, eggs, and cooled onion mixture. Mix only until evenly combined.
Shape into a rectangular loaf on the prepared baking sheet. Spread the ketchup evenly over the top.
Bake uncovered for 60 to 70 minutes, until an instant-read thermometer inserted into the center registers 160°F. To keep the top from cracking, set a pan of hot water on the oven rack below the meatloaf.
Let the meatloaf rest for at least 10 minutes before slicing and serving.