Wash the broccoli thoroughly
Trim off the leaves and tough stems
Cut the broccoli into small florets
Peel and slice the stems if you want to freeze them too
Blanch the broccoli in boiling water for 3 minutes
Transfer immediately to ice water for 3 minutes
Drain the broccoli well
Pat it dry with a clean towel
Spread the broccoli in a single layer on a baking sheet
Freeze until solid
Transfer the frozen broccoli to freezer bags or airtight containers
Remove as much air as possible
Label with the date
Store in the freezer for up to 12 months