Mix together paprika, brown sugar, chili powder, garlic powder, and cayenne in a small bowl. Set aside. Makes about ½ cup.
Seasoning can be made 1 month ahead. Store airtight at room temperature.
CHICKEN MARINADE
Combine lemon zest and juice in a large bowl. Add chicken thighs. Use tongs to toss to coat. Sprinkle with salt and 4 tablespoons BBQ seasoning and toss again to evenly coat. Cover and let marinate for 1/2 hour to 2 hours in the fridge.
BBQ SAUCE
Heat oil in a medium saucepan over medium. Add onion and garlic to the pan, stirring occasionally, until tender, about 3 minutes. Next, add brown sugar and cook, stirring constantly, until sugar turns a shade darker, about 2 minutes. Add remaining 1 tablespoon bbq seasoning and continue to cook, stirring, until fragrant, about 30 seconds. Then add ketchup and cook until slightly darkened in color, about 2 minutes. Lastly, stir in vinegar, molasses, mustard, hot sauce, and Worcestershire sauce. Bring to a boil and cook for 2 minutes stirring occasionally. Let cool 5 minutes.
Transfer to a blender or food processor and purée/blend until smooth, approx 2 minutes. Set sauce aside.
Short cut tip: If short on time, use a gluten free bottled bbq sauce in place of the homemade bbq sauce but don't skip the bbq seasoning or marination.
BBQ-ing
Heat grill to medium-high heat. Spray grill with oil. Place chicken skin-side-up on the grill. Cook for 10 minutes covered. Check on chicken after 5 minutes to make sure there are no major flare ups. If so, move pieces around and possibly reduce heat to medium to avoid more flare ups. Then flip chicken pieces over and cook for 5 minutes, covered. Both sides of the chicken should be browned and charred.
Now we start saucing and turning every couple of minutes or so, until thoroughly browned, caramelized and cooked through, about 10 minutes more (an instant-read thermometer inserted into the thickest part of thighs should register 165°). Total cooking time will be approx. 25 minutes.
Remove chicken from the grill and place on a large platter. Serve with any extra bbq sauce you may have.
Notes
I prefer thighs but any chicken parts can be used for this recipe... breasts, wings and/or drumsticks.