Pick your flowers freshly from the fields and rinse them well to get rid of any impurities and insects. It helps to add a cap of vinegar to the water to get rid of insects when washing the flower heads.
Keep dandelion flowers to dry for 2-3 days in the sun. The flowers can be dried in a dehydrator too but sundried dandelion petals are better.
After they are dried, pick out the yellow flower blossom and keep them in a bowl. Discard the green parts, those are bitter.
Pour water into sauce pan and add flower pieces. Bring to a boil, cover and keep over slow fire for about 1 hour. Allow it to simmer slowly.
After cooking, when the water has been infused, strain the juices from the flowers well and press out all the juices of the flower. Discard the flower pieces.
Take the strained liquid back to the heat together with the sugar and lemon juice and squeezed out lemon halfes. Mix well and bring to a boil. The sugar quantity depends on the quantity of the strained liquid, if you have 1 quart you need 2.2 pounds sugar (*see Notes). The ratio is 1:1 water and sugar.
Stir well and let it cook slowly until the jelly sets OR until you are satisfied with the consistency (*see Notes). Skim and remove the foam on the jelly.
Check if the jelly is good with a candy thermometer. The right temperature is 220 Fahrenheit/ 105 Celsius. You can also test if it is done, by dropping some hot jelly on an ice-cold plate. If it runs a lot it's not ready and needs more cooking, if it's not running but appears like honey, it is ready.
In the meanwhile, sterilize the 2-3 Jars and keep a few drops of rum (or vodka or other) into the inner jar lids. That will help to preserve the jelly for a longer period. Fill your sterilized jars to the rim, close with the lid and turn upside down to create a vacuum.
Leave it upside down overnight. The next day, label your jelly and store in a cool and dry place. Store in the fridge once opened.
Video
Notes
The flowers need to be picked freshly with the head opened and not closed. Pick only flowers from untreated (nonpoisonous) fields.
You can add one orange (juice and skin, without the white flesh) to your cooking flowers. That helps in adding natural pectin to the jelly. The original recipe included orange but I have been skipping it lately to keep it simple.
Important: Add as much sugar as you have infused dandelion water. Measure after straining the liquid left. 1 liter =1 kilo sugar, 1 quart = 2.2 pounds. The ratio is 1:1. I.e with one liter water I ended up having 700 milliliters infused water after cooking and therefore added 700 grams sugar.
Dandelion jelly won't set the way a red currant jelly sets because it lacks fruit pectin. That is why I think honey is a better name. However, you can cook it down further to increase the thickness. It's fine if it is a honey consistency (see picture and video) and it will last for 5-10 months unopened in a cool and dry place. Keep in the fridge once opened.