The best frozen zucchinis are the ones you never knew were frozen. When you freeze zucchini the right way -- a quick blanching, a quicker cool-down then into the freezer ASAP -- you don't have to worry about thawing them in out in six months and getting a soggy mess for your trouble. That's because blanching and cooling stops the enzymes that make zucchini lose quality in cold storage. For best results always freeze firm, blemish-free zucchinis at the height of ripeness, ideally within a day of their harvest.
Wash the zucchinis under cool running water and bring a pot of water to a boil. Set a colander in the sink.
Cut the zucchinis into pieces at least 1/2 inch thick. It doesn't matter if you cut the zucchini crosswise into coins or dice them into cubes, but pieces smaller than 1/2 inch thick don't hold up well to freezing.
Blanch the sliced zucchini in boiling water for 3 minutes then transfer it to the colander. Run cold water over the zucchini until it's cold to the touch, at least 3 minutes.
Drain the zucchini for several minutes then place it an even layer on a tray or plate. Pat the zucchini dry with a paper towel and let it air dry for a couple minutes.
Place the zucchini in heavy-duty freezer bags and squeeze out as much air as possible before sealing. Mark the date on the bags and place them flat in the freezer. Use the zucchini within 6 months for best results.