In a large bowl with a wire whisk together flour, yeast, baking powder, sugar and salt.
Cut the butter in with a fork, or your fingertips, until it crumbles into small pieces.
Add egg yolks and then warm milk. Mix to combine.
Transfer to a floured surface.
Knead until the dough is smooth; form a ball and put it in a bowl; cover and let it rest for 15-20 minutes.
While the dough is resting prepare the filling. Mix egg whites until foamy, add sugar and keep beating until firm peak forms. Use a rubber spatula to fold in the walnuts.
Preheat the oven to 360F.
Divide the dough in four equal parts. Take one dough ball, place it on a lightly floured surface (you can use a silicone mat or parchment paper) and roll using roll pin to the size of a pan.
Transfer your first layer to the prepared pan (13″ x 9″), pull off parchment if using, and cut off any excess dough. If the layer is not big enough to cover the pan just press it with your fingertips until it fits.
Spread one third of apricot jam over the entire layer, and then spread one third of the walnut filling.
Repeat procedure with a second and third layer and then cover the cake with a fourth layer.
Using a fork poke few holes on the top layer.
Bake 30 minutes or until golden brown. Remove from the oven, put on a wire rack, and let it cool.
For chocolate glaze add oil to chocolate chips and microwave for 1 minute. Stir with a spoon until melted and then pour evenly over the cake until fully covered.