Gently combine all the meatball ingredients, except for the olive oil, in a large bowl. Form the turkey mixture into 1-inch balls - you should get approximately 24 meatballs.

Heat 1 tablespoon olive oil in a heavy medium skillet. Add 1 cup pasta sauce. Place meatballs in single layer in sauce. Spoon remaining sauce over. Bring to simmer. Cover; reduce heat to medium-low and simmer until meatballs are almost cooked through, stirring occasionally, about 10 minutes. Remove from heat.

Meanwhile, cook the penne as instructed on the package. Once cooked, add it to the skillet with meatballs and sauce.

Preheat oven to 375F.

Combine the ricotta, spinach and 3/4 cup of shredded mozzarella (save the 1/4 cup for later). Add to the meatballs. Pour the meatballs, penne and ricotta cheese mixture into a large lightly greased casserole dish.

Top the casserole dish with reserved mozzarella and place into the oven and bake for 40 minutes until the top is golden brown. Remove from oven and let sit for 10 minutes before serving.