received baking wisdom suggesrs four varables that can make the fruit sink and these are: mixture a little too wet, oven a little too cool fruit has a sugary coating which dissolves and lubricates the fruits journey downward, fruit wet or juicy, ditto ditto. so...rinse the sugar off the fruit then dry well and shake in a little flour, (I meant the fruit, stop giggling at the back there) try raising the oven temp just slightly and if you are a hobby baker, then consider investing in an oven thermometer to check your cooker temp regulatoreither reduce the amount of liquid in your mix or increase the amount of flour...best of luck.