Ah, there's nothing like a nice filling pasta dish. Can eat warm and heated up at work for lunch as I did this week - just slap it in the fridge.
Ingredients:
Olive oil
300g macaroni
2 leeks, chopped
50g butter
50g plain flour
1 1/2 pints of milk
half a teaspoon of wholegrain mustard (optional)
250 g cheddar cheese
2-3 slices of bread (to make into breadcrumbs)
1 generous tablespoon of chopped parsley, dry or fresh
salt and pepper
25g extra cheese (grated) for the topping
How to:
1. Pre-heat the oven to 180 degree or Gas Mark 4. Then add the macaroni to a large pan of boiling water and the oil and a bit of salt.
2. Chop the leeks and also add to a large pan of boiling water - then simmer for around 10 minutes to soften. I cut mine diagonal and then in half again to create nice ribbons.
3. In the meantime, make the cheese sauce by bringing a hob to full power and melting the butter. Once this is melted, add the flour into the butter and mix well. Make sure you have a large pan for this as you will be adding 1 1/2 pints of milk to this in a mo!!
4. Then add the milk (and the mustard if you are having it) and take back to the hob. Bring the sauce back to the boil, then immediately take off the heat. This will take a bit longer than you think - mine took about 10 minutes to get to this stage so you may want to think about this when timing everything.
5. Add the cheese to the hot sauce slowly and stir well. Then drain the leeks and stir these in as well. Then add the parsely, salt and pepper to taste and mix everything together.
6. Once the macaroni is cooked, drain this and add to the sauce as well.
7. Move all the mixture to a large caaserole dish (it should fill it!) and cover over with the breadcrumbs. If you want to add more cheese on the top here (maybe a mozzarella or a double gloucester) then this would be very tasty. I was greedy and used all my cheese in the sauce so had none left 
8. Place in the central shelf of the oven uncovered for about 30-40 minutes until the breadcrumbs and cheese (if using) on top are nice and crispy and brown.
9. Serve with a nice green salad.
