Sweet Potato and Gouda Frittata

Heat the butter in an ovenproof 10-inch / 25 cm saute pan over medium-high heat until the butter is almost brown. Add the sweet potato and season to taste with salt and pepper. Cook for 5 to 7 minutes or until the sweet potato is almost tender, shaking the saute pan back and forth occasionally.

Stir in 1 teaspoon sage and cook for 1 minute longer, stirring constantly. Transfer mixture to a bowl to cool.

Wipe out the saute pan and add 2 tablespoons olive oil. Heat over medium-high heat until the oil is hot; add the mushrooms and onion. Season with salt and pepper. Cook for 10 minutes or until the mixture is softened and slightly brown. Stirring occasionally. Add to the sweet potato mixture. Cool for 10 minutes.

Preheat the oven to 350º F / 180º C. In a medium bowl, whisk the eggs until blended and stir in the milk. Season with salt and pepper. Add the sweet potato mixture, cheese, parsley and remaining sage and mix well. Wipe out the saute pan and coat the bottom and side with 1 to 2 teaspoons olive oil. Pour the egg mixture into the prepared pan, smoothing out the top.

Cook over low heat for 5 to 6 minutes or until the edges begin to set. Bake for 15 minutes or just until set in the center. Remove from the oven and cool on a wire rack for 10 to 15 minutes. Loosen the frittata by gently running a plastic spatula around the edge. Place an inverted plate onto the top of the pan and quickly flip the frittata over onto the plate. Repeat this process back onto another plate so that the frittata is now right side up and ready to be sliced.