Spoon your spinach and ricotta mix into a piping bag and set in the fridge for later.
Ensure you have two sheets of pasta large enough to cover a 9cm ring.
Lay one sheet on the bench and pipe a circle of the filling centrally, leaving a space in the centre for the egg yolk.
Very gently add the yolks, they need to stay whole.
Use your finger and a pot of water to dampen the pasta around the edge of the spinach and ricotta circle, then lay the second sheet of pasta over the top. Seal the pasta around the filling, squeezing any air out to the edges.
Use a 9cm ring to cut the raviolo and crimp with your fingers or a fork.
Boil a pan of water and season with salt.
Gently drop both raviolos in the water and simmer for 1.5-2 minutes.