Hi Noni, thank you for your message! I make this specific recipe also with other kinds of fruit, and it always turns out perfectly.
I think the 'problem' is the tart pan choice. Yours is smaller than the one I use, which is 26 cm / 10 inches. The batter will be in a thicker layer, which increases the baking time. Also, all ovens are different, so baking times can also vary a bit. Always check if the cake or pie is completely done before removing it from the oven. You can easily check with a wooden skewer, if it comes out clean the cake is done.
Have a great day, with love, Véronique