In a large bowl, add cubed sweet potatoes, olive oil, salt, and pepper. Mix well.
On a baking sheet, add sweet potatoes, bake for 30 minutes at 375 degrees. Set aside to cool, for 10 minutes.
Place Sweet potatoes in a large bowl, using a fork, mash sweet potatoes, until smooth.
Then add ground turkey, spinach, garlic, onions, chicken Bovril, ground pepper, breadcrumbs, and eggs, mix until fully combined.
Lightly spray a loaf pan with cooking spray, and place sweet potato mixture evenly inside. Cover with foil and place in oven at 375 degrees for 30 minutes, then remove foil and bake for additional 15 minutes, until cooked.