Grease a baking pan with margarine and line a with baking paper, the size according to your taste (I use 24×24 cm).  Sift all dry ingredients (flour, cornstarch, and milk powder).  Preheat the oven to medium heat, around 180°C.

Then mixer all the ingredients together at high speed for about 2-3 minutes, until it expands and is thick with an almost pale color of the dough, and there are no large bubbles on the surface of the dough. 

After that put it in the pan and slightly beat it so that the dough is evenly distributed in the pan or flatten it with a skewer and bake until cooked.  Check with a skewer if it's not sticky, it means it's cooked.

After the two layers of yellow and brown are cooked, let it cool a bit and then spread with strawberry jam and stack both layers and slightly pressed, then cut off the edges.  Then let it sit for a while then cut into pieces according to taste.

Note :
And vice versa with the chocolate layer, the method is the same and because I don't have a special surabaya layered pan with a partition so I work twice on the dough and baking process.