Instructions:
Preheat the oven to 375°F.
In a large sauté pan, melt the butter over medium heat and add the garlic. Cook until golden brown, 1-2 minutes.
Add the onions and cook until translucent. Toss in the spinach and cook until wilted. Drain the water from the spinach and set aside to cool completely.
Meanwhile, in a medium skillet, cook the franks until well browned. Remove from the pan and julienne.
Once the spinach is cool, add the turkey, franks, salt and white pepper to the spinach and toss to combine. Spray a 9 x 13-inch glass baking dish with vegetable cooking spray, then spread out the turkey, sausage and spinach mixture on the bottom of the pan.
In a medium mixing bowl, whisk together the eggs, cream, nutmeg, provolone and mozzarella, and pour into the baking dish. Sprinkle the parmigiano-reggiano cheese evenly over the top.
Bake for 25 to 30 minutes, or until a knife inserted in the center comes out clean.
Remove the frittata from the oven, place on a rack to set for about 5 minutes, and serve.