Wash the broccoli thoroughly
Cut into florets of similar size
Peel and slice the stems if desired
Bring a large pot of water to a boil
Prepare a bowl of ice water
Blanch the broccoli florets for 2 to 3 minutes
Blanch the stems for 3 minutes if using
Transfer immediately to the ice water
Cool completely for the same amount of time as blanching
Drain well
Pat dry with a clean towel
Spread broccoli in a single layer on a baking sheet
Freeze until solid
Transfer 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