Pre-heat your oven to 375 degrees.
Rinse your chicken well (you want that bird really clean) and pat it dry with paper towels. Season generously with kosher salt and coarse black pepper. Make sure you season the cavity too.
Melt the butter in a medium Dutch oven over medium-high heat. When bubbling slightly add the chicken and brown well on all sides. This should take about 10 minutes. Please be very careful about dangerous butter spatter, capiche?
When brown, remove the chicken to a plate and pour the butter left in the pot into a small bowl. (You can discard the butter if you like, or you could also use it for vegetables, potatoes, etc. The latter is a good idea.) Quarter one of the zested lemons and pop it into the chickenâ??s cavity. Return the chicken to the pot and add the lemon zest, cinnamon stick, garlic, sage and milk. (If you want crispy skin, place the chicken in the pot breast-side up. If you don't care about the skin, and want even more insanely juicy breast meat, put the chicken breast-side down.)
Put the lid on your Dutch and roast for 1 hour and 15 minutes. Remove the lid, baste the chicken with some of the cooking liquid and roast uncovered for another 15 minutes. (1 hour and 30 minutes total. Duh.)
To serve, pull the meat from the bones and spoon lots of the â??sauceâ?? over top. Get some vegetables and potatoes/grains involved if you like.