I’ve not heard of this method to preserve basil. I usually take the leaves, stack them, chiffonade them, put bunches into a quart ziploc freezer bag, add at least a quarter cup olive oil, more if you need to so all is coated. Squish everything around so all the basil is coated. Flatten, close and freeze. So easy to break off what you need for a pasta dish, pizza or anything else. I make pesto too and freeze the same way.
Thanks!