Bring a pan of boiling water to a simmer with a pinch of salt. Lower in the gnocchi and cook for 3 minutes or until they float to the surface. Strain, then leave to drain in a colander while you make the sauce.
Heat the butter in a large frying pan and cook over a medium heat until foaming and lightly golden. Add the sage and walnuts, and cook for 2-3 minutes until the sage is crisping up and the nuts are toasted; don’t allow the butter to darken too much. Remove the sage and nuts with a draining spoon, leaving the butter behind.
Add the drained gnocchi to the pan and toss until they start to turn golden and crisp, and the butter is nut-brown. Season well. Transfer to a shallow bowl and top with the walnuts, sage and grated Parmesan. Serve with a mixed leaf salad, if you wish.
