If the mash has been made in advance you will need to warm it up a bit in a saucepan, do not overheat. Add the butter and stir till melted in, add seasoning and nutmeg and egg yolk and mix again.
Finally fold in the flour, do nott overwork as that is what causes those horrid bullet type gnocchi!
Split the dough into 3 parts and roll into long sausage shapes on a lightly floured surface.
Cut into 1" pieces, roll into balls and then squish slightly on the pronged end of a fork to give nice ridges for the pesto to cling to.
Bring a large pan of salted water to the boil and drop in the gnocchi. When they float to the top leave for just 1.5 mins before removing with a slotted spoon and allowing to dry on kitchen paper.
Heat a frying pan with a dash of olive oil and butter and gently fry the gnocchi till golden brown both sides.
Drain on kitchen paper.
Blitz all ingredients in food processor and be thrilled by the gorgeous vibrant green colour and zingy taste!
Serve the gnocchi on a pool of pesto and garnish with some extra rocket leaves that have been lightly tossed in lemon juice and olive oil.
Add some shavings of fresh parmasan and enjoy!