Any special tricks for freezing these?
The way I do it is just bring a big pot of water to boil...drop the broc and caulie in the pot for about 4 minutes, drain and immediately cool in cold water. Drain and allow to cool completely. Pack in containers and freeze.
I do the exact same but mine go in freezer bags, the stock is good to freeze for soups or use the stalks from the broccoli and make a cream of broccoli soup right away. I am cheap, all my scraps go in the freezer for soup.