Preheat oven to 180°C (160°C fan-forced), lightly grease a 12cm x 36cm rectangle tart tin with removable base and line base with baking paper.
To check if the pastry is the correct size for the tart tin, place the tart tin over the pastry, there should be at least a 3.5cm border the whole way around. Carefully line the tart tin with the pastry, gently push the pastry into the sides of the tin, cover and chill in the refrigerator while you make the filling. Re-freezer remaining pastry or cut and bake as biscuits.
To make the coconut frangipane, cream butter, sugar and zest together using a stand mixer, until pale and fluffy. Add eggs, one at a time, beating until each has been incorporated, don’t overbeat. Add the desiccated coconut, ground almonds and cornflour, mix until well combined.
Spread the raspberry jam over the base of the prepared tart shell and spoon the filling on top, spreading evenly. Sprinkle over the coconut flakes pressing gently into the filling.
Place tart tin in oven and bake for 35-40 minutes, or until the frangipane is puffed and pastry is golden.