01 - Rinse the dandelion flowers thoroughly under cool running water. Remove all green parts from the flower heads, retaining only the bright yellow petals.
02 - Combine the cleaned petals and water in a saucepan. Bring to a boil, then reduce the heat and simmer gently for 10 minutes.
03 - Remove the saucepan from heat and let the mixture steep uncovered for 30 minutes to develop full floral flavor.
04 - Pour the mixture through a fine mesh sieve or cheesecloth, pressing firmly to extract all liquid. Discard the spent petals. Measure the reserved liquid; it should yield approximately 3 cups.
05 - Pour the measured liquid into a clean pot. Stir in the lemon juice and fruit pectin until fully dissolved. Bring to a full rolling boil over high heat, stirring constantly.
06 - Add the sugar all at once. Return to a rolling boil and cook for 1 to 2 more minutes, stirring constantly to prevent scorching.
07 - Remove from heat and skim off any surface foam. Immediately ladle the hot jelly into sterilized jars, leaving a 1/4-inch headspace. Seal with lids.
08 - Process the sealed jars in a boiling water bath for 10 minutes for long-term storage, or allow to cool and refrigerate for immediate use.