Heat the oil in a large frying pan and add in the onions. Cook for 3 minutes on a medium-to-high heat until they start to turn translucent. Add in the chicken, salt and pepper. Cook for a further 3 minutes until the chicken is sealed (it won’t be cooked in the middle at this point).
Add in the garlic, tomato puree and red peppers. Stir, then add in the pasta. Now add in the oregano, Worcestershire sauce, tins of tomatoes, stock and milk. Stir and bring to the boil, then turn down to a gentle simmer. Cover with a lid or some foil and simmer for 12-15 minutes (checking occasionally) until the pasta is cooked.
Stir in the chopped sugar snap peas (it’s nice to add them at the end, so they’re hot, but retain their crunch), then sprinkle the pasta with cheese and put it under the grill/broiler for a couple of minutes until the cheese has melted.