Peel and grate the rutabaga, apple and onion
Place the grated fruit and vegetables in a bowl and mix.
Place all of the batter ingredients in a blender and mix to a smooth consistency.
Preheat the oven to 435°F.
Heat the oil in a cast iron skillet.
Place the vegetables in the frying pan and allow to slightly sauté.
Pour the batter over the cooking vegetables and smooth out.
Allow to cook 2-3 minutes on the stove-top, then place in the oven and bake for 18-20 minutes.
When the top of the frittata is lightly browned and the mixture is solid in the center, remove from the oven and allow to set and slightly cool.