Harvest dandelion blossoms from a clean, un-sprayed location. The blossoms should be whole open dandelion flowers.
Carefully remove the dandelion petals (yellow parts), removing all the green parts. Do not leave any green parts, as they're bitter (but technically edible). From 1 quart of blossoms, you should get about 1 cup of petals.
Place the dandelion petals in a quart jar and cover with 750 ml of vodka (or neutral spirit). Cap with a tight fitting lid and shake to mix.
Allow the mixture to infuse for about 2 to 3 weeks, shaking every few days.
Once infused, strain through a fine mesh strainer.
Sweeten to taste with a light honey or sugar. I'd suggest about 1/4 cup for this recipe, but use more or less as it suits you.
Bottle and store, or enjoy immediately.
Notes
Once strained, this liqueur will keep indefinitely, but some of the flavors will start to fade after about a year. If you like it, plan on making a fresh batch each year.