Add the bacon and minced beef, pork and garlic. Cook for a further 10 minutes, stirring constantly until the meat is coloured all over. Season with salt and pepper.
Pour in the wine or stock, stir well and cook for five minutes until the alcohol has evaporated. Add the passata, tomato purée and oregano. Lower the heat and cook, uncovered, for one hour, stirring occasionally, until you get a beautiful rich sauce. Season to taste.
Preheat the oven to 180ºC/fan 160°C/gas 4.
For the white sauce, melt the butter in a large saucepan over a medium heat.
Stir in the flour and cook for one minute until it becomes light brown in colour.
Gradually whisk in the milk. Lower the heat and cook for 10 minutes, whisking constantly.