Set aside 2 large Ziploc bags. Wash the chicken thighs and pat them dry. Place the chicken thighs inside 1 Ziploc bag.
In a medium bowl combine chopped basil leaves, lemon juice, zest, olive oil, garlic, celery salt, salt, paprika, and dried parsley. Whisk to combine. Pour the marinade mixture inside Ziploc bag with chicken thighs. Close the Ziploc bag and shake it around to distribute the marinade on the chicken thighs.
Open second Ziploc bag and place closed Ziploc bag with the chicken thighs inside. You don't really have to do this, but I like to make sure my chicken is sealed. Place the bag in the refrigerator with a plate underneath. Marinate chicken thighs for "as long as you want".
I marinated this overnight, but you can marinate anywhere from 15 minutes to 24 hours. - Depends on "How much time you got". Give the Ziploc bag an occasional shake to distribute that marinade.
When you've marinated that jammy long enough, preheat the oven 350 degrees Fahrenheit. Place chicken thighs in a roasting pan. Very LIGHTLY sprinkle salt over surface of the thighs and cover with aluminum foil. Alternatively, you can use a Dutch oven with a lid, which is how I cooked my chicken thighs.
Cook, covered for about 55 minutes, basting occasionally. Baste more often if your marinate time was short. Remove lid (or aluminum foil) and cook uncovered for another 30 minutes until the skin has somewhat browned. Remove from oven and allow chicken to cool for a few minutes.
Serve garnished with basil leaves and lemon slices. Or don't garnish it. It's your jam.