The perfect sausages for this dish are those from specialist Italian or Continental delicatessens, luganega, which come in one long length. If you are using ordinary sausages, add a teaspoon of fennel seeds to the onions when frying.
Put together healthy veg with a yummy mustard and cheese sauce and you've got a great pasta bake. Each serving provides 459 kcal, 24g protein, 63g carbohydrate (of which 6.5g sugars), 11g fat (of which 5.5g saturates), 6g fibre and 0.6g salt.