Put the prepared mince in a large, heavy pan with the onion,bacon, chopped celery, carrots and garlic. Dry-fry over a medium heat, stirring well from time to time, for approx. 10 minutes until it turns brown while the veggies are slightly colored.
Toss in the mushrooms and stir-fry for 2-3 minutes. Add the stock, tomatoes, purée, bay leaf and dried oregano.
Stir well and bring it to the boil, then simmer very gently for 25-35 minutes while keeping it uncovered. (stirring occasionally)
Let the sauce bubble for a further 10 minutes on medium heat till it becomes thick and rich., or until rich and thick. Stir regularly atthis time to avoid sticking.
On the other side, cook your spaghetti according to the packinstructions. Drain well and divide between warmed bowls. Top with theBolognese (removing the bay leaf), garnish with the oregano.