I make a carbonara sauce with quark all the time - had it for tea tonight! & it is yummy!
I mix a tub of quark with 2 eggs until smooth, add loads of fresh ground black pepper and put to one side.
Finely dice an onion and fry it off until soft in a large frying pan, with 2 cloves of crushed garlic. Add some chopped up bacon and fry until crisp.
Meanwhile boil a large pan of spaghetti.
Drain the spaghetti (doesn't need to be completely drained as liquid will help sauce), reserve a 1/4 cup of the pasta water.
Mix the water with the quark mixture.
Remove the frying pan from the heat, add the quark and stir in the pasta. Toss the mixture until pasta is completely covered and serve
I also add a chopped chicken breast into mine ... nom nom!