Preheat the oven to 400°F. Lightly spray a 9x9-inch baking dish with cooking spray.
Add the sweet potatoes and 1 inch of water to a large pot. Cover and bring to a simmer over medium heat. Cook for 10–12 minutes, or until the sweet potatoes are almost tender when pierced with a fork.
Carefully remove the lid and add the broccoli. Cover and cook for another 3–5 minutes, or until the sweet potatoes and broccoli are tender. Drain well.
Return the sweet potatoes and broccoli to the pot. Add ½ tsp. salt, ¼ tsp. pepper and 1 Tbsp. milk. Mash with a fork or potato masher until creamy. Add the remaining 1 Tbsp. milk if needed. Set aside.
While the veggies cook, heat the olive oil in a large skillet over medium heat. Add the onion and cook for 4–5 minutes, stirring occasionally, until softened.
Add the ground turkey to the skillet. Break it into small pieces with a spatula and cook for 6–8 minutes, or until fully cooked.
Add the garlic, oregano, paprika and remaining ½ tsp. salt and ¼ tsp. pepper. Stir and cook for 1 minute.
Stir in the tomato paste until the turkey is evenly coated. Add the chicken broth and simmer for 5 minutes.
Spread the turkey mixture evenly in the baking dish. Spoon the sweet potato and broccoli mash on top and spread into an even layer.
Bake for 25–30 minutes, or until the filling is hot and bubbling around the edges.
Carefully remove from the oven and sprinkle with pecans and Parmesan cheese, if using. Bake for 5 more minutes.
Let cool for a few minutes before serving. Top with sliced green onions, if desired, and enjoy!