Season the pork with salt and freshly cracked pepper.
Heat the butter and oil over medium heat in a casserole dish, and brownthe meat on all sides for about 10-15 minutes. Remove meat.
Add the onion and garlic, sauté until soft, add sage leaves and lemon rind to the casserole dish.
Slowly pour the milk into the casserole dish, add meat, bring it to a boil, and then turn down the heat on the stove to a lower medium setting.
Cover the casserole dish (with a lid partly off) and cook slowly in a 325 oven for 1 ½-2 hours until the meat is easily pierced by the tip of a knife. Turn the meat occasionally. If necessary, add a little more milk as needed to help baste.
Remove the meat and place it onto a serving platter and keep it warm.
Cook the remaining milk that is left in the casserole dish on the stove until browned and thickened into clusters of milk. The milk should look like cottage cheese.
Pour the browned milk into a blender and blend until smooth (so the milk is not separated). If it becomes too thick, add 2-3 tablespoons of warm water.
Thinly slice the meat and spoon the browned milk over the top. Enjoy!