Time: 1 Hour
Preheat the oven to 180C/Gas 4
Cook the macaroni in a pan of boiling water for 8-10 minutes, until just cooked. Drain and place into an oven proof dish.
Heat the oil in a large frying pan and saute the leeks for 2-4 minutes until soft. Add the butter and stir until melted before adding the flour.
Keep stirring until the mixture starts to bubble and then slowly add the cider followed by the milk.
The mixture will start to thicken, so keep stirring until you have a smooth sauce. Add the mustard and half the cheese and season with salt and pepper.
Pour the sauce over the macaroni and stir together well. Sprinkle over the rest of the cheese and then the breadcrumbs and thyme.
Bake in the oven for 30-40 minutes until golden and bubbling and serve with a green salad.