If you want to surprise your guests. Unusual cake with berries and delicate cream

Ingredients:
-Greek yogurt - 200ml
-sugar - 200 g
-butter - 200 g
-flour - 550 g
-baking powder - 12 g
-cocoa powder - 1 tablespoon
-1 egg + 4 egg yolks
-sugar - 125 g
-vanilla extract or sugar
-corn starch - 50 g
-hot milk - 500 ml
-butter - 100 g
-berries - 250 g
The size of the finished dessert - 15,5*21 cm
Bake for 20 minutes at 180°C
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