Preheat the oven to 200°C or 392°F (bottom and top heating with air circulation).
Wash the chicken breast to remove any remaining bones or other unwanted bits. Dry it on paper towels and season with salt and pepper.
Place in a heatproof dish, drizzle with olive oil and place in a preheated oven. Bake for 10 minutes, then remove and add the following:peeled garlic cloves, lemon zest, cinnamon stick, sage leaves. Then pour the milk over it and cover with aluminum foil. Put it back in the oven and bake under the foil for about 45 minutes, then remove the foil and bake for another 15 minutes. During this time, turn the chicken a few times and baste it with the milk.
Check that it is soft enough and that the outside is crispy. When ready, remove from the oven, cover, and leave to rest for 15 minutes. This will make it even more crumbly.