Summarize the following:
Do so by cutting the leaves off with a knife, or by gently using your fingers to pull them from the stalk. Put about 1 spoonful of leaves in each section, then top the leaves with water and freeze the trays. This creates perfectly-portioned cubes that are easy to simply drop in soup and sauce recipes as desired. Once the fennel ice cubes have frozen completely, transfer them to a plastic bag or storage container to keep them fresh.

Summary:
Remove the leaves from the stalk to preserve fennel tops. Freeze small portions of fennel in an ice cube tray. Transfer the frozen cubes to a storage container.