Method
Preheat oven gas 6 /200/400. Put a large saucepan of water on to boil and add a tsp or two of salt once boiling add the sweet potato and cook for about 10 minutes then take out the sweet potato with a slotted spoon and put into a large bowl, Keep the water boiling and add the macaroni and stir well and cook for 8-10 minutes until cooked but still quite firm then drain in a colander.
Using a fork mash the sweet potato in the bowl till mashed but not pureed. Add the tub of quark, the cooked macaroni and 100g of the grated cheese and mix well.
In a saucepan place the milk and the cornflour and bring to the boil, Keeps whisking all the time until the sauce is thick and cook for a couple of minutes to lose the floury taste. Season with salt and pepper then add to the sweet potato, macaroni and cheese mixture and again mix together very well. Taste for seasoning (I found it needs quite a lot of salt and pepper. )
Tip it all into a large casserole dish and sprinkle the remaining 60g of grated cheese on top and sprinkle on the quarter tsp paprika,
Place the casserole dish on a baking tray and bake in the oven for 30 minutes until browned and hot.
Credit : http://vicki-kitchen.blogspot.co.uk/