Prepare Kathi's Chocolate Cake Mix as directed, using the eggs, butter, and water.. Pour the dough evenly into a well floured and greased 10-inch springform pan (26 cm). Bake as directed approx. 45 minutes until toothpick comes out clean.

When cool, remove cake from pan and cut it horizontally in half to make two layers. Place one layer on a cake plate and enclose with a cake setting ring.

Place gelatin sheets in warm water, let soak and dissolve as directed. Let the liquid cool down.

Meanwhile stir plain yogurt until smooth. Fold 1 tbsp yogurt into the dissolved gelatin. Now fold this mixture into the remaining yogurt.

Put heavy whipping cream, sugar and vanilla sugar into a bowl and beat until stiff peaks form. Fold the yogurt, once it is gelling, carefully into the stiffened whipped cream.

Cover the first cake layer evenly with a little of the whipped cream-yogurt mix, cover it evenly with pineapple pieces.

Add the top cake layer and spread the rest of the yogurt-cream evenly on top.

Refrigerate the cake for at least 3 hours.