Nowithstanding this is a) too late and b) posted in the wrong forum, here's how I would do it. Half way through cooking your sausages in the frying pan add some finely chopped onion. When the sausages are almost cooked and are browned all over, remove the from the pan. Add 1 tablespoon of plain flour to the fat and onions in the pan and stir to make a roux. Cook on a low heat for a couple of minutes to cook out the flour taste. Turn the heat up and pour in your cider a little at a time as if making a regular white sauce. When it has reached the consistency you want, reduce heat to a simmer and return the sausages to the pan to finish cooking.