01 - Rinse the dandelion flowers thoroughly under cool water. Pull away and discard all green parts from the flower heads, keeping only the yellow petals.
02 - Combine the yellow petals and water in a saucepan. Bring to a boil, then reduce heat and simmer gently for 10 minutes.
03 - Remove the saucepan from heat and let the mixture steep uncovered for 30 minutes to draw out the full floral flavor.
04 - Pour the mixture through a fine mesh sieve or cheesecloth, pressing firmly to extract all liquid. Discard the spent petals. You should have approximately 3 cups of infused liquid.
05 - Transfer the measured liquid to a clean pot. Stir in the lemon juice and fruit pectin until fully dissolved.
06 - Bring the mixture to a full rolling boil over high heat, stirring constantly to prevent scorching.
07 - Pour in the sugar all at once. Return to a rolling boil and continue cooking for 1 to 2 minutes, stirring without interruption.
08 - Remove from heat and skim off any surface foam. Ladle the hot jelly immediately into sterilized jars, leaving 1/4-inch headspace. Seal with lids.
09 - Process the sealed jars in a boiling water bath for 10 minutes for extended shelf storage, or let cool and refrigerate for immediate use.