Blanch the tomatoes in slightly salted boiling water, peel them, deseed them and slice them into fillets. Wash and finely chop the onion, the celery, and the carrot, then dice the bacon.
Heat the oil in a saucepan, add the onion mix and lightly fry until soft then add the bacon. Brown it, add the tomatoes and season with salt and pepper. Simmer for 30 minutes, stirring from time to time.
Cook the bucatini in plenty of slightly salted boiling water. Drain them al dente, mix them with the sauce, mix well and serve warm.