Requires: potato ricer or tamis (drum sieve) and plastic wrap (cling film)
Wash the potatoes and place in a large pot (unpeeled). Cover with cold water and bring to the boil. Add a pinch of salt and cook, uncovered, until the potatoes are tender all the way through (approximately 30-40 minutes after the water has come to a boil).
Drain the potatoes and let them cool slightly. Prepare a medium sized bowl to place the mashed potatoes. Cut the potatoes in half and place cut side down into a potato ricer. Remove the potato skins each time you place a piece of potato into the potato ricer.
Alternatively, remove the potato skins and mash using a tamis (drum sieve) into a bowl.
Mix the egg yolks into the mashed potato, then add the Parmigiano Reggiano. Gradually stir in the flour one spoon at a time, then transfer to a lightly floured work surface. Work in enough flour and knead gently until a soft, light dough forms.
Divide the dough into four portions. Cover three of the portions with plastic wrap (cling film) to keep them from drying out. Lightly flour the work surface and roll one of the portions into a long rope about 1.5cm in thickness. Cut the rope into gnocchi (approximately 1.5cm in length). Take each piece of gnocchi and roll one at a time down the tines of a fork, letting it drop onto a lightly floured surface at the end. This motion will give the gnocchi their signature ridges. Arrange the gnocchi onto a very well-floured tray. Repeat with the remaining dough.
Note: Steps 1-4 can be completed several hours in advance. Gnocchi can also be frozen.
Bring a large saucepan of salted water to the boil over high heat. Reduce the heat to medium and add the gnocchi in batches (they will sink to the bottom). Stir gently and cook until the gnocchi float to the surface. Remove the gnocchi with a slotted spoon, transferring to a large bowl. Repeat with remaining gnocchi. Reserve 2 tablespoons (40ml) of the gnocchi cooking water.
To make the creamy gorgonzola sauce, melt butter in a large non-stick frying pan over medium heat. Stir in the cream and gorgonzola. Bring just to the boil, then reduce heat to low. Gently simmer for a few minutes until the sauce thickens slightly. Remove from the heat.
Add the cooked gnocchi and reserved gnocchi cooking water to the frying pan with creamy gorgonzola sauce. Toss to combine, then spoon gnocchi into serving bowls. Top with grated Parmigiano Reggiano and chopped walnuts. Serve immediately – buon appetito.
30g butter|200g gorgonzola cheese, crumbled (preferably gorgonzola dolce)|200ml thickened cream|8 walnuts, roughly chopped|Parmigiano Reggiano, finely grated to serve|Sea salt, freshly ground black pepper