In a large pot of boiling water cook the gnocchi according to the directions on the package. Strain and reserve.
In a pan melt butter with sage leaves until the butter bubbles and turns slightly gold, this is also commonly referred to as beurre noisette. Put in the lemon zest,and both cheeses. Turn off the heat, add in the strained gnocchi. Shake the pan until you see the cheese melting in the butter making a thick opaque sauce. Or you can simply stir using a wooden spoon until all the cheese is melted into the butter. Add in freshly cracked Pepper and a pinch of salt to taste.
Whenever I am plating pasta I always put some grated cheese at the bottom of the dish to soak up any water or liquid and its another opportunity to flavor the dish!
Garnish the top with fresh sage leaves.