Set your chicken into a container/dish that will be suitable for storing it in the fridge. Juice your grapefruit completely, setting aside the fresh juice in a bowl and saving all of the rind.
Drizzle olive oil all over the chicken and rub it in well. Pour half of the grapefruit juice over the chicken. Then sprinkle the chopped garlic cloves, fresh dill, salt, and pepper on top. Rub everything into the chicken thoroughly on all sides. Rotate the chicken so that it's facing breast-side down in the marinating flavors.
Cover and refrigerate the other half of the grapefruit juice, which will be used when its time to roast. Stuff the chicken with the leftover grapefruit. And feel free to also stuff the chicken with any extra dill or stems. Cover and refrigerate for 48 hours.
When its time to cook the chicken, remove it from the fridge 1 hour before baking so that it can warm-up a bit. Preheat the oven to 350º F.
Rotate the chicken so that it is facing breast side up on a baking dish or sheet pan. Drizzle it with a little more olive oil, making sure that the pan beneath it is oiled a well, and add a little more fresh salt and pepper on top. Gently sprinkle the garlic granules over the entire top of the chicken, but don't rub them in (this sets a crispy garlic crust that bakes beautifully onto the skin!). Roast the chicken for 30 minutes.
At the first 30-minute mark, remove the chicken from the oven and gently pour the remaining grapefruit juice all over the chicken. Return to the oven and roast for 30 minutes more.
At the second 30-minute mark, the garlic granules should be baked into the skin firmly. So now you can baste the chicken using a basting brush. Dip the brush into the run-off juices and pat them onto the chicken skin. Return the chicken to the oven and roast for approximately 60 minutes more, or until an internal-read thermometer reaches 165º F. Feel free to baste another time or two while its roasting for these final 60 minutes.
When done, remove the chicken from the oven and allow it to rest for 10 minutes before slicing. Enjoy!
