1) Mix little cider with corn flour to make a paste.
2) In a saucepan, heat the remaining cider.
3) Remove from heat and mix the hot cider with cornflour paste.
4) Return the paste to the pan and boil while stirring.
5) In the pan, add raisins and pineapple and heat the mixture.
6) Let the sauce get cool and serve along with desserts.