Peel the onions and garlic, trim the carrot, celery and courgette. Finely chop or coarsely grate all the veg, then stir it into the pan with 1 tablespoon of olive oil.
Cook for 10 to 15 minutes, or until the vegetables are soft and sweet, stirring occasionally.
Add the mince, breaking it up with a wooden spoon, then turn the heat up a little and cook for 5 minutes, stirring regularly until the meat is browned and the veg is nicely golden.
Scrunch in the tomatoes through clean hands, then half-fill each tin with water, swirl it around to pick up all the last bits of tomato and pour into the pan.
Mash everything up with your spoon, add a pinch of black pepper, reduce the heat to low and leave to cook for 2 to 3 hours, or until thickened and reduced.
About 15 minutes before you’re ready to serve, cook the spaghetti in a large pan of boiling salted water according to the packet instructions, then drain. Use tongs to divide between bowls, then spoon over the Bolognese and serve with a good grating of cheese.