Pat the chicken dry with paper towels and turn the chicken breast side down on the board. Using strong kitchen scissors ( the Jamie Oliver ones I have are great), start at the tail and cut up each side of the backbone and cut the backbone out.
Turn chicken breast side up and press down with the heel of your palm onto the breast bone until you hear a snap.
The chicken should now be flattened and ready for flavor bombing!
How to flavor and roast the butterflied chicken
Preheat oven 200C/400F
Take a long strip of rind off the lemon using a potato peeler (or as much lemon as you want). You don't want any white pith. Reserve the lemon.
Using a mini food processor or similar appliance, process lemon rind, herbs, garlic and chilli flakes, if using, with 1/4 extra virgin olive oil until finely chopped and looks a bit like pesto.
Season with 2 teaspoons salt and freshly ground pepper
Place the chicken in a roasting pan breast side down. Squeeze over the juice half of the lemon,
Spoon a 1/3 of the herb/oil mixture over the chicken and spread evenly and into all crevices.
Turn chicken over breast side up. Squeeze over the juice of the remaining lemon half.
Slip your fingers gently between the breast and the skin to make a pocket to fill with goodness.
Spoon some of the herb/oil mixture into the pocket you have just made then spoon and spread the rest over the chicken.
Drizzle over remaining oil and sprinkle with extra salt (or to your taste).
Roast for 1 hour. Check at 50 minutes. (see recipe notes)
When cooked, remove and cover with loosely with foil to rest for 10 minutes.
Any fresh herbs can be used - I like to use a combination of basil, parsley and at least 1 tablespoon of fresh rosemary leaves. If I have fresh tarragon or thyme that's lovely too. But the bulk of the herbs are made up of basil and parsley.
Take the chicken out of the fridge for 20-30 minutes so that it can come to room temperature. Obviously, be sensible about this, if it's a stinking hot summers day the chicken will come to room temperature as you prepare it. The main thing is that a cold chicken will take longer to cook and you will have to adjust times to suit and then you risk drying out the breast meat.
To know if the chicken is done, you can use a thermometer. I have read that you should check in the thickest part of the thigh which should read somewhere between 75C/165F - 80C/175F. Which is fine but use your commonsense. If the juices run clear, that's done and the meat should be firm not jiggly. I like the blood near the bone to be cooked and that only happens at about 85C/185F