Cut the fresh pasta sheet(s) into 36 circles using a pastry cutter.
Remove the skin from the goat's cheese and break into small chucks.
Crush the walnuts and add to the goat's cheese along with the salt pepper an double cream. Mix until you have a smooth paste.
Place a small amount of the filling in the middle of one of the pasta circles and brush around the filling with some egg yolk.
Take another pasta circle and place on top of the filling. Seal the edges of the raviolo making sure not to leave any pockets of air. Use a crinkled pastry cutter to trim off the edges.
Continue until you have 18 ravioli.
For the butter sauce:
Chop the chives and cut the butter into small cubes.
Bring the water to the boil and then start whisking in the butter one cube at a time. Making sure the butter emulsifies with the water. Continue until you have a smooth and glossy sauce.
Add the seasoning and the chives to the sauce.
Cook the ravioli for 3 minutes in salted boiling water. Drain and serve immediately with a drizzle of the butter sauce.