Add olive oil and the ground or finely chopped pancetta to a heavy, nonstick casserole pot (aluminum, cast-iron, and terracotta pots are also acceptable).
Cook over medium heat until the pancetta has melted.
Once melted, set the heat to low, and add the finely chopped root vegetables. Cook, stirring constantly, until softened.
Up the heat to medium, add the meat, and cook until sizzling and browned, about 10 minutes. Make sure to break up all the lumps during those 10 minutes.
Pour in the wine and cook until evaporated, then add the tomato paste and the strained tomatoes and mix.
Pour in a cup (120 ml) of boiling stock (or water) and simmer for 2-3 hours, depending on preference and the type of meat. While simmering, add more hot broth or water as needed.
Halfway through cooking, pour in the milk and make sure it completely evaporates by the time the ragù is done.
The finished ragù should be thick, glossy, and a rich maroon color.
