How to Make It
In a large bowl, combine the ricotta with the Fontina, mozzarella and Parmigiano-Reggiano and season with salt and pepper. Add the egg and stir until incorporated.
Ravioli can be prepared over two days. Mix the filling on day one, store it in the fridge overnight, then make the dough and assemble the ravioli the next day. Freeze for up to a month.
Minerally, full-bodied Italian white.