Beat egg yolks with 4-5 tablespoons warm water until creamy. Beat egg whites until stiff, fold in sugar. Mix all ingredients, form into a 26 cake springform pan and bake at 200 degrees for about half an hour.
Mix the sour cream or crème fraiche with the sugar mixture, whip the cream until stiff and add to the cream, finally fold in the vanilla cream powder.
Cut the sponge cake base once and place the 1st layer in the cake springform pan. Spread all the cream evenly on top. Cover with the 2nd layer. Raspberries on the top layer form. Spread cake glaze evenly over top. Place in refrigerator to set.