step 1
Preheat the oven to 200C/fan 180C. Cook the macaroni.
step 2
Heat the oil in a pan and add the garlic and leeks and allow to soften.
step 3
Melt the butter in a pan.Stir in the flour gradually.
step 4
Add the milk gradually, stirring to avoid lumps.Add the mustard.
step 5
Add the cheese and stir the mixture until it has melted into the sauce.
step 6
Stir the leeks into the sauce. Add the cooked pasta.
step 7
Put the mixture into an oven proof dish, top with cheese and bake for 20mins.