If the gnocchi are not to be cooked right away, they should be frozen. The gnocchi can be made up to two weeks in advance and frozen on sheet pans. Once they are frozen solid they can be transferred to a sealable bag or wrapped tightly to avoid freezer burn. Do not thaw them before cooking or they will stick together. To cook them, throw the frozen gnocchi directly into the boiling salted water without thawing. Their cooking time will be slightly longer than unfrozen but their preparation should be completed in the same manner as with fresh gnocchi.