Peel your onions and cut 1/2 inch off top and bottoms. Place the onions in a large saucepan and cover with boiling water. Cook until tender, about 20 minutes, drain.
Cool them slightly and carefully remove the inside layers of the onions, separating into 8 individual shells and then drain on paper towels.
In a skillet, cook your turkey and sausage over medium heat until it is not pink then drain and add spinach to it and cook another 2 minutes. Remove and stir in the remaining ingredients. spoon into shells.
Put the onions in a greased 13x9 inch baking pan and bake uncovered at 350 degrees for 15 to 20 minutes or until lightly browned.