100g spinach, blanched & squeezed of excess liquid
100g parmesan, grated, plus more to serve
1 lemon, zested
A pinch of nutmeg
10 sage leaves
To make the pasta dough, place the flour and eggs in the food processor and pulse until you are left with a crumbly mixture. You can also make by hand by making a well in the flour, pouring the eggs into the hole and slowly incorporating the eggs into the flour. Form it into a ball, cover with cling film and set aside in the fridge for 30 minutes.
While the pasta is resting, prepare the filling by combining the chopped spinach, ricotta and parmesan. Season with the lemon zest, pepper and a pinch of nutmeg - if the mix is too thick, loosen with a little milk. Transfer the mixture to a piping bag fitted with a large round nozzle.
Take your dough out of the fridge and cut in half. Roll out one half with a large rolling pin on a floured work surface. You may need to take rests between rolling, to allow the gluten to relax again, but be patient and the pasta will reward you. Roll it as thin as you can - so that you can see your hand through the dough.
Cut the rolled pasta in half lengthways, so you have 2 sheets. Pipe on approx 6-8cm circles of the ricotta mixture to one sheet of the dough - leaving 5cm between each one. Brush around the filling with egg yolk and then lay another sheet of pasta on top, pressing gently to tease out any air pockets and seal.
Cut out the ravioli and discard the scraps. Place the ravioli on a plate dusted with semolina and repeat with the other half of the pasta dough.
Bring a large pot of water to a steady boil and season with sea salt and lower the ravioli into the water. Cook for 3-4 minutes or until al dente. At the same time that the pasta is cooking, melt the butter in a hot frying pan and add the sage leaves, frying until they are crisp and the butter is golden brown and nutty.
Drain the ravioli and transfer to the butter and sage mixture. Swirl to coat and serve with more freshly grated parmesan, and a generous amount of freshly ground black pepper.