Made with the blanch-then-process technique,

pesto will remain bright and fresh in the refrigerator
for several days. If you want to keep it for even
longer, freeze it. The best way to do this is to fill an
ice cube tray with the pesto and allow it to freeze
overnight. The next day, pop out all the cubes and
place them in a zipper-lock freezer bag. Pesto can be
frozen for up to 6 months like this. To use it, cut a
pesto cube into rough pieces on your cutting board,
then thaw them in a skillet or directly in the
saucepan with the cooked pasta.