Meanwhile whisk together the eggs and cottage cheese. Fold in the Gruyere cheese, melted butter, salt & pepper and thyme. Sprinkle the flour and baking powder over the egg mixture and stir to combine.
Pour the egg mixture over the potatoes and turkey mixture and spread evenly to cover. Place the skillet in the oven and bake for about 50 minutes until a knife inserted in the center comes out clean. Serve the frittata hot.