Heat oven to 200C/180C fan/gas 6. Season the chicken, rub with ½ tbsp oil, then put in a large roasting tin with the garlic and roast for 25-30 mins.
Meanwhile, blitz the herbs, anchovy, capers, lemon juice and remaining oil with some seasoning in a food processor until finely chopped. Set aside.
Once the chicken is cooked, remove the tin from the oven and squeeze the garlic out of their skins. Tip in the rice and use a wooden spoon to break it up, then add the spinach and lemon zest and toss. Return to the oven for 5 mins. Divide between bowls and dollop on the salsa verde.