Peel the potatoes, peel and deseed the squash, then dice both into 1 inch pieces. Cook the potatoes and squash in boiling salted water for 12 minutes, then drain and cool. Wrap them in a kitchen towel and squeeze, then purée them using the bamix® multi-purpose blade. Sprinkle in the flour, grate half of the nutmeg in the bamix® processor and add to the mixture, season well with sea salt and black pepper and mix well. Knead the mixture with the bamix® multi-purpose blade for a few minutes until smooth, then divide into four portions. Form into ropes about 3/4 inch thick and cut off pieces of gnocchi that are 1/2 inch in width. Pluck off the parsley leaves and chop them finely with 1 pinch of salt in the bamix® processor. Peel the garlic, add it and chop it too, then put the walnuts in the bamix® processor and process everything into a paste. Stir in 4 tablespoons of oil and add the Parmesan. Squeeze in the juice of the lemon, mix everything together and season the pesto to taste. Cook the gnocchi in two batches in boiling salted water for 2-3 minutes each - as soon as they rise to the surface, they are ready. Lift them out with a skimmer and place them on a plate - within 30 seconds they will become firmer. Either toss each portion in half of the pesto with a splash of the gnocchi water or spread the pesto on a plate and arrange the steaming gnocchi on top.
