Combine 80 g flour, 70 g cornstarch, and 250 g sugar in a saucepan.

Whisk in about 200 ml of the milk until the mixture is smooth.

Bring the remaining milk to a boil on the stovetop.

Whisk the starch mixture into the boiling milk.

Cook the cream while whisking until thickened.

Cover the cream directly with parchment paper and chill it completely.

Separate the eggs into two mixing bowls.

Beat the egg whites until foamy and gradually beat in 250 g sugar.

Beat in the egg yolks, 200 ml oil, and 200 ml warm water.

Sift 350 g flour, baking powder, and cocoa powder together.

Fold the dry ingredients into the egg mixture until no dry streaks remain.

Divide the batter equally between two parchment-lined baking sheets.

Bake both sponge layers at 180°C for 10 min.

Cool the sponge layers completely and cut matching rounds with a cookie cutter.

Beat the chilled cream with 300 g softened butter and vanilla sugar until smooth.

Spread cream between two sponge rounds to make sandwich cakes.

Roll the cake sides in desiccated coconut.

Melt the chocolate with 15 ml oil until glossy.

Spoon chocolate glaze over the top of each cake and let it set.