Preheat oven to 350 degrees.
Prepare chicken by removing neck and giblets (if needed) from the chicken and discard (or freeze if you’d like to save for making gravy). Rinse chicken, inside and out, under cool water and pat dry with paper towels. Place the chicken in a casserole dish or rimmed baking sheet large enough to leave at least an inch around the chicken on all sides and tall enough to catch juices from the chicken as it bakes.
In a small bowl, mix 1 tablespoon honey, 1 tablespoon dijon mustard and garlic powder. Using your hands, pour and distribute the mixture as far under the skin as you can on all sides of the chicken. Rub any excess on the outside as well.
Smash or roughly chop the garlic cloves and put them along with the quartered onion in the cavity of the chicken. Rub the olive oil, salt and pepper on all sides of the outside of the chicken, then return it breast side up in the dish.
Bake for 80-95 minutes or until thermometer inserted into the thickest part of the breast reaches 165 degrees. Let rest for 10 minutes before slicing and serving.
While the chicken rests, combine the remaining 1 tablespoon honey and 1 tablespoon dijon mustard in a small bowl. Brush or drizzle on the chicken prior to serving.