Preheat the oven to 180° C. 

Mix the flour and the baking powder, then whisk together with butter, sugar, eggs and salt until combined.

Fill the batter into a round 30cm baking tin laid out with a baking sheet. Gently press the dough to an even surface and create a 1-2 cm rim around the edges.

Peel the apples. Then halve the apples and nectarines, cut out the core, then slice them into thin half-moon shapes. 

Place the apples and nectarines neatly into a circle, working your way from the outside to inside. I like to take turns with one row of apples following by a row of nectarines, because it creates a nice flower pattern. In the picture above you should be able to see what I mean.

For the flan, mix the powder with the milk and the apple juice in a small pan. Over medium heat, bring to a boil while constantly stirring. Take it off the heat, and stir in the cream. Then bring it to a boil again.

Take it off the heat and stir in the egg yolk. Immediately spread it evenly over the cake.

Bake it ca. 45-50 minutes, until the dough on the side is golden brown. Take the cake out and let it cool for about 10 minutes, then take it out of the tin and transfer it to a rack. 

When cooled, decorate the cake with blueberries.