Preheat your oven and a 10" cast iron skillet to 375-425F (your choice. Honest).
Wash and dry the chicken well.
With kitchen shears, cut down either side of the backbone. Save it for stock.
Turn the chicken skin side up on a cutting board and press down firmly to flatten him out. You will hear some cracking sounds. Try not to think about it.
Rub a bit of olive oil evenly on both sides of the chicken.
Lightly salt and pepper both sides. Set the chicken aside.
Evenly distribute the onions, carrots, celery and lemons in a 12" cast iron skillet.
Sprinkle the vegetables with a bit of kosher salt and pepper. Sprinkle on about a teaspoon of the Citrus Fennel Sea Salt (or whatever you're using).
Place the chicken, skin side up, in the skillet. Season with another teaspoon or so of the Citrus Fennel Sea Salt.
Put the chicken in the oven on the center rack. Roast for 15-20 minutes.
Open the oven and put the 10" skillet (or your bricks) on top of the chicken and press down lightly.
Continue to roast until the breast meat reads about 155F and the thigh meat reads 175F, another 15-25 minutes, depending on your oven temperature and the size of your bird.
Remove from oven and carefully move the chicken to a warmed platter. Cover with foil and let rest while you're cooking the couscous.
Pour out the pan drippings through a strainer and reserve for the couscous.
Measure the pan drippings, if you have less than a cup, add water or stock to make up the difference.
Taste the liquid and add a pinch of salt if necessary (ours didn't need it because we did not have to dilute our drippings)
Heat a medium saucepan over medium heat until hot.
Add the butter and oil.
After the foam subsides, pour in the couscous.
Stir to coat the couscous and let toast until a lovely, toasty color.
Pour in the cup of liquid. Stir and cover.
Reduce heat to medium-low and let simmer until done, about 10 minutes for the brand we used. Check your package directions.
Serve with your beautiful chicken and vegetables.
Make sure to take the chicken out of the fridge at least an hour before cooking so he can come up to temperature a bit.