For the base: Preheat the oven to 180 degrees C (350 degrees F). Lightly grease a 20-by-30-centimeter slice tin (8-by-12-inch baking pan).
Place the flour and softened butter into a bowl and rub together until it resembles breadcrumbs. Add the caster sugar, coconut and baking powder and mix to combine. Add a splash of cold water to bring the mixture together and gather into a dough. Press into the bottom of the prepared tin and bake until golden in color, 15 to 20 minutes. Allow to cool.
For the filling: Spread the jam over the cooled base and top with the sliced berries.
For the topping: In a food mixer (stand mixer), whisk the caster sugar and eggs together until light and fluffy, approximately 5 minutes. Add the oats, almonds and coconut to the egg and sugar mix and fold to combine. Pour the mixture over the base and filling.
Bake until the top is golden, a further 15 minutes. Set aside to cool in the tin. To serve, remove from the tin and cut into squares.