Spatchcocked chicken, a classic of Portuguese cooking, is essentially a chicken that is cooked flat - a technique that allows the chicken to cook evenly on the grill. The chicken is split down the back and flattened (the word may come from "dispatch the cock"). In this way, the juices are concentrated and the chicken stays moist and flavorful.

Here's the technique:

1. Place the chicken breast-side down on your work surface. 
2. Using a wide-bladed knife or poultry shears, cut down along the whole length of the backbone.
3. Repeat on the other side of the backbone.
4. Remove the backbone.
5. Turn the chicken over, cover with waxed or parchment paper and press down forcefully to flatten the chicken and break the joints so that the chicken sits very flat. Some cooks use a heavy cast iron pan on the chicken to distribute the weight over the whole surface. 
6. Voilà - your chicken is spatchcocked.
7. At this point, we recommend sliding your hand between the breast meat and the skin to detach the skin. You can insert some herbs for grilling, or a stuffing or some flavored butter for oven roasting.