Place the dried ceps in a bowl and cover with warm water. Leave to soak for 25–30 minutes, until plump and soft. Drain, reserving the soaking liquid, and roughly chop the mushrooms.
Rinse the spelt and place it in a saucepan. Cover with plenty of fresh water, bring to a simmer and cook uncovered for about 25 minutes, or until just tender. Drain well.
Return the pan to the heat and add one-third of the butter. When melted, add the shallots and garlic and cook gently for 4–6 minutes until softened. Add the chopped ceps and cook for a further 5 minutes. Spoon half of the mushroom and shallot mixture onto a board and leave to cool. Add the cooked spelt to the remaining mixture in the pan along with half the chives and half the thyme leaves. Season well with salt and pepper.
Once cooled, mix the reserved mushroom mixture with the remaining soft butter and the rest of the chives and thyme. Season to taste. Gently loosen the skin from the chicken breast and spoon the mushroom butter underneath, spreading it evenly. Rub any remaining butter over the outside of the bird and season generously with salt and pepper.
Preheat the oven to 180°C (160°C fan) / 350°F. Place the chicken in a roasting dish. Spoon the spelt mixture into the cavity and spread any extra around the base of the chicken. Pour over the reserved mushroom soaking liquid. Roast for approximately 1 hour 20 minutes, basting the chicken and stirring the spelt occasionally so it doesn’t dry out. Allow the chicken to rest for at least 15 minutes before carving and serving.
