In a large bowl, combine cheeses, parsley, egg, and nutmeg. Season to taste with salt and pepper, and stir until smooth. Set aside.
To use filling for ravioli, place fresh pasta on a lightly floured work surface and use a sharp knife or pizza cutter and ruler to trim the pasta into 3-inch squares.
Transfer filling to a pastry bag, and pipe 2 teaspoons Robiola filling in the center of each square. Lightly brush or spray the edges of each square with water and cover with another pasta square. Press the pasta with your fingertips to seal the ball of Robiola inside, making sure to press out all of the air. Trim the edges with a zigzag pasta wheel and set on a parchment-paper-lined baking sheet lightly dusted with flour or cornmeal. Continue with the remaining pasta and filling until all the squares are filled.
Bring a large pot of salted water to a boil. Add ravioli and cook until they rise to the surface, 3 to 5 minutes, then cook for 1 minute longer or until the centers are cooked through and the pasta is al dente. Remove with a skimmer or slotted spoon to a large bowl. Once they are all removed, drain any water from the bowl.
This filling may be used to make a variety of filled pastas, such as agnolotti, ravioli, and tortelli.