1. Pre-heat the oven to 190°c / gas mark 5.
2. Leave the butter out of the fridge for a while to soften. In a bowl, mix together the butter with the spice paste until well combined.
3. Rub the flavoured butter all over the surface of the chicken to completely coat it. Place in the pre-heated oven for around 1 hour and 20 minutes, or until when a skewer is inserted into the thickest part of the meat, the juices run clear. Exact cooking times will depend on the size of the chicken. Baste the chicken with the juices part way through cooking to keep it moist. If the surface of the chicken is getting to dark, you can cover it with tin foil and return to the oven to finish cooking through. Leave to rest for 10 minutes.
4. Meanwhile place the baby carrots and chopped red onion onto an oven proof tray and drizzle with olive oil, salt and pepper. Roast in the oven until golden and tender.
5. Take a saucepan and add in the quinoa and the water. Bring to the boil, then reduce to a simmer and cook out until the water has been absorbed and the quinoa is tender and fluffy. Season with salt and pepper.
6. For the sauce, simply mix together the yogurt, coriander and lemon juice with a hand blender until smooth and well combined. Keep in the fridge until ready to serve.
7. Mix together the roasted carrots and red onion with the quinoa. Serve this alongside the spicy roast chicken and the cooling yogurt sauce.