In a large mixing bowl combine whole grain flour, brown and granulated sugar and salt. Add the butter cubes and rub in with your fingers until the mix looks like fine crumbs. You can also use a pastry knife. Add the ice water and combine everything to a dough. Chill in the fridge for 30min to 1 hour.
In a large pot bring the water to simmering temperature
Add the peeled and thinly sliced apple in a steamer basekt to the pot and steam for 10 minutes until soft.
Let cool to room temperature and combine the apples with the spice and brown sugar.
Preparing the apple pie batter
In a bowl of a stand mixer combine the butter with the sugar until light and fluffy. Add eggs and mix until incorporated.
In a septerate bowl combine the flour, baking powder and salt. Slowly add to the mixer and beat until combined. Add heavy cream and mix until smooth. Set aside.
Making the cake
Preheat the oven to 180°C and prepare a 24cm springform pan with butter and flour.
Flatten the dough into a disc and roll the dough out with a floured rolling pin As you are rolling the dough, turn the dough circle a couple times to make sure it is not sticking to the counter and add more flour to your work surface as needed. Transfer the dough circle to pan. To transfer the dough without tearing it, loosely wrap the pie dough around your rolling pin and then unroll it over your springform pan. Trim the edges so there is only about a bit of overhang
Place half of the apple pie batter on top of the crust, spreading until smooth. Top with all the apples and the layering the rest of the apple pie batter.
Cover with foil and bake for 40 minutes. Remove the foil and bake 20 minutes, until golden brown.
Let cool to room temperature before serving. Dust with confectioners sugar.