Käsesahnetorte (German Yogurt Mousse Cake) Recipe

Ingredients

• 3 large eggs, separated, divided
• 3 tablespoons warm water
• 0.75 cup white sugar
• 1 teaspoon vanilla extract
• 4.5 ounces cake flour, sifted
• 0.5 teaspoon baking powder
• 1 pinch salt
• 2 cups heavy cream
• 0.33333334326744 cup cold water
• 1 (.25 ounce) package unflavored gelatin
• 2 cups Greek yogurt
• 1 cup white sugar
• 0.25 cup lemon juice
• 0.25 cup confectioners' sugar, or as needed