Freezing Brussels Sprouts
1. Select green, firm and compact heads. Examine heads carefully to make sure they are free from insects.
2. Trim, removing coarse outer leaves.
3. Wash thoroughly in cool water.
4. Sort into small, medium and large sizes.
5. Water blanch small heads 3 minutes, medium heads 4 minutes and large heads 5 minutes.
6. Cool promptly in ice water,
7. Drain and package in Ziploc or vacuum bags, leaving no headspace (excluding as much air as possible).
8. Seal and freeze.
Also see this page for Pickled Brussels Sprouts (or Cauliflower)