put milk,onion,peppercorns and bay leaf in a pan and bring to the boil.remove from the heat and let stand for 15mins.

melt the butter in a pan and stir in the flour until well combined and smooth.cook over a medium heat,stirring constantly,for 1min. remove from the heat. strain the milk to remove the solids and stir a little into the butter and flour mixture until well incorparated.return to the heat and gradually add the remaining milk,stirring constantly, until it has all been incorparated.cook for a further 3 minutes or until the sauce is smooth and thickened,then add the nutmeg,cream and pepper to taste. add the cheddar and roquefort cheese and stir until melted

meanwhile,bring a large pan of water to the boil. add the macaroni,then return to the boil and cook for 8-10minutes, or until just tender. drain well and add to the cheese sauce.stir well together.

preheat the grill to high.spoon the mixture into an ovenproof serving dish,then scatter over the gruyere cheese and doritos(broken) and cook under the grill untill bubbling and brown