Start by mixing 1 cup of water with 1 cup of milk and the beef stock cube in a pot or pyrex dish. Heat/warm the liquid and stir till the cube dissolved and your liquid for the roux is ready.
In a large pot boil the pasta in salted water according to the packet instructions and strain and set aside once cooked. Reserve a cup of the pasta water if needed for later.
In a large saucepan melt the butter and add the flour and whisk well. Cook this mixture for about 2 minutes. We want to cook out that raw flour taste.
Add in the nutmet and mix well and then slowly add in the liquid mixture while whisking constantly. You want to make sure you don't have a lumpy roux. So add the liquid in slowly as you keep whisking.
Once all the liquid has been poured in and you have a lump free sauce add in the cheese and whisk till it's melted and fully incorporated.
Then add in the cooked pasta and mix well. And your macaroni and cheese is ready.
For this serving I would recommend just pan frying about 2 chicken breasts or 300g of chicken breast after seasoning with just salt and pepper and then chopping it into squares. Add in about 250g of mixed frozen vegetables after cooking them and making sure they are tender.