01 - Rinse the dandelion flowers thoroughly under cool running water. Pull away all green parts from the flower heads, keeping only the bright yellow petals.
02 - Combine the cleaned 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 petal liquid 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 strained liquid, which should yield approximately 3 cups, and pour into a clean pot.
05 - Stir the lemon juice and fruit pectin into the measured liquid. Bring to a full rolling boil over high heat, stirring constantly.
06 - Add all of the sugar at once. Return to a rolling boil and cook for 1 to 2 minutes, maintaining constant stirring to prevent scorching.
07 - Remove from heat and skim off any surface foam. Immediately ladle the hot jelly into sterilized jars, leaving 1/4-inch headspace. Seal with lids.
08 - Process sealed jars in a boiling water bath for 10 minutes for shelf-stable storage, or let cool and refrigerate for immediate use.