Start by preparing the ragout. Finely chop carrot, onion and celery and add to a pan with a little olive oil, then cook until brown. Add the mince and cook for a few minutes, then raise the heat, add wine and simmer until the liquid has reduced. Add the tomato sauce, a little sugar, a bottle of water and salt to taste. Simmer for 2-3 hours on a low heat. For the white sauce, bring the milk to a boil. Melt the butter in a saucepan over a low heat, then remove from heat, add flour and whisk. Return to a low heat and gradually whisk in the hot milk. Season with salt and nutmeg, then whisk constantly until the sauce thickens (about 15 minutes). At this point cut the Caciotta Nonna Emma into cubes, grease the sides of the oven pan with butter and layer the lasagna, starting with the meat sauce, then cover with a layer of lasagne sheets and top with the white sauce and the Nonna Emma cubes. Repeat until you finish the layers, then sprinkle over some grated Pecorino and bake for 20 minutes at 180 °C or until crisp and golden brown on top.