Preheat Oven to 210CPrepare oven tray with a quick spray of cooking spray and baking paper (best method for getting paper to stick!)Prepare your chicken, dice your camembert, and grated cheese and set aside.Add the self raising flour and salt to a medium bowl.Dice your butter into small pieces and add to the flourBegin to rub the butter into the flour with your fingers, until the flour resembles fine breadcrumbs and no large pieces of butter remain - this can take a good few minutes so be patient (I am not....)Add the dried rosemary if using and gently combine.Pour the milk into the flour mixture and using a round ended butter knife begin to cut through the flour until the milk begins to combine.Flour your bench and tip out the ingredients and gently knead to combine.Using a rolling pin roll out your dough into a rectangle approximately 1 cm in height - approx. 40 x 30cmCover the base in plum sauce, add the chicken, then Camembert, then a little more plum sauce drizzle if you like and finally the first measure of grated cheese, leaving a small 0.5cm edge around.Begin tightly rolling from one of the longest edges ensuring the mixture stays in the roll and keep the roll tight until you reach the end - you can dab a little milk along the last edge so that the roll sticks to itself whilst cutting.Once you have a log formed - begin to slice 2 cm portions and pop on the tray, leaving 1-2 cm in betweenTop with a little additional grated cheeseCook for 18 minutes or until golden brownRemove from oven, serve warm or cold.