Pre-heat the oven to 200°C. Grease and line a baking sheet with nonstick baking paper.
Place the flour in a shallow dish and season it well. Place the beaten egg in a shallow dish and combine the breadcrumbs in a shallow dish as well. Dredge the chicken breasts in the flour, then shake off any excess. Dip in the egg, coating well, then roll in the breadcrumbs. Arrange on the baking tray and bake for 25-30 minutes until the breadcrumbs are crisp and golden and the chicken is firm and cooked through, with no pink showing.
Meanwhile, combine all the ingredients for the tomato puree in a small saucepan. Bring to a simmer over a moderate heat and cook for 10-15 minutes, stirring occasionally until reduced and thick.
When the chicken is towards the end of its cooking time, cook the spaghetti in a large saucepan of boiling, salted water until 'al dente'; usually 10-12 minutes. Remove the chicken from the oven and top with the grated mozzarella. Return to the oven for 5 minutes to melt.
Drain the spaghetti when ready and leave to cool for a minute.
Meanwhile, heat the olive oil for the spaghetti in a large saucepan over a moderate heat until hot, then fry the garlic for 1 minute, stirring frequently. Add the spaghetti, the chopped herbs and some seasoning. Toss well and serve in rolls on plates.
Remove the chicken and cut the breasts in half. Re-heat the tomato puree if necessary and spoon onto the plates. Sit the cut chicken on top and serve.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.