4sprigs of fresh dillI chose to trim the stalks off and left only the dill fronds
Add the vinegar, sugar, salt, celery seed, and red pepper flakes to a 2 to 3-quart saucepan over medium-high heat. Stir the vinegar mixture constantly until the sugar completely dissolves. Remove the pan from the heat. Allow the vinegar mixture to rest for 10 to 15 minutes, until completely cooled.
Alternate layers of the sliced cucumber, onion, and fresh dill in the quart canning jar.
Once the vinegar mixture is cooled, slowly pour over the cucumber and onion. Allow the salad to marinate for 15 minutes before serving.