Gather fresh dandelion petals, rinse under cold water, and place in a heatproof container. Pour 4 cups of boiling water over the petals, cover, and steep for 8-12 hours.

Strain the mixture through a fine mesh sieve or cheesecloth into a large pot, discarding the petals, to obtain a bright yellow liquid.

Combine the strained dandelion infusion with 1/4 cup of lemon juice in the pot. If using pectin, add it according to package instructions.

Bring the mixture to a rolling boil over medium-high heat, stirring constantly to prevent sticking.

Gradually add 4 cups of granulated sugar while stirring until completely dissolved, and the mixture becomes glossy.

Boil intensely for 10-15 minutes, then check for the setting point using a candy thermometer or the wrinkle test.

Remove from heat, skim off any foam, and ladle hot jelly into sterilized jars, leaving 1/4 inch headspace.

Process the jars in a boiling water bath for 10 minutes to seal properly.

Cool jars on a towel or cooling rack and check seals after 24 hours.

Store sealed jars in a cool, dark place for up to one year; refrigerate opened jars and consume within 3-4 weeks.