Place a rack in the upper third of the oven and preheat oven to 350 degrees F. Lightly spray a 9-inch pie dish with nonstick cooking spray and set aside.
Turn the ExactSlice™ lever to the thinnest setting. Run the sweet potatoes through the Food Processor shoot, creating very thin, round, sweet potato slices.
Place sweet potato slices, overlapping and layered, across the bottom and sides of the greased baking dish. Layer 2 or 3 layers of sweet potato across the bottom and sides. Set aside.
In a medium skillet over medium heat, cook the sausage, breaking up the sausage with a spoon as the sausage cooks. Cook until golden brown, crisp and cooked through, about 6 minutes. Remove from heat and layer atop the sliced sweet potatoes in the pan, leaving and sausage grease in the pan.
Add onions to the pan of sausage grease and cook over medium heat. Cook until the onions are translucent and just beginning to brown, about 5 minutes. Add the kale and cook down for 4 minutes more. Add the onion and kale mixture atop the sausage in the pan.
In a medium bowl whisk together half and half, eggs, salt and pepper. Whisk until very well combined.
Crumble goat cheese over the frittata filling. Pour the egg mixture over the frittata filling.
Place in the oven and bake until the eggs are puffed and just golden brown, about 25 to 30 minutes. Remove from the oven and allow to cool for at least 30 minutes before slicing and serving warm or at room temperature.