Preheat the oven to 180°C.
Mix the butter/spread with the thyme, minced garlic and lemon zest.
Place the chicken in a roasting dish. Rub inside and out with the butter, then season with salt and pepper. Put one half of the lemon in the in the cavity of the chicken together with the whole garlic.
Bake for about 20 minutes, then turn the chicken onto its breast. Squeeze the lemon juice all over it and cook for another 25 minutes before turning it back to breast-side up (while letting the juice out of the cavity). Baste the chicken with the pan juices and cook for another 50-60 minutes or so, until it’s golden and an inserted skewer between the thighs result in clear juice coming out.
When the chicken is cooked through, take it out of the oven, transfer it to a plate, cover with foil and tea towel and rest for 15 minutes before carving.
Serve with side dishes of your choice.and the pan jus poured over (alternatively make gravy with the pan juices).