This Austrian Marbled Bundt Cake is a traditional Austrian cake. It is super delicious, airy, and tastes like vanilla and cocoa.
Preheat oven to 320°F / 160°C. Lightly grease and flour a 10-inch (24cm) bundt pan. Set aside.
In a small bowl stir cocoa and 3 tbsp water to combine. Set aside.
In a medium-sized bowl, stir flour, baking powder, and salt to combine. Set aside.
Separate egg yolks and egg whites into two large mixing bowls. With a handheld or stand mixer fitted with a whisk attachment whisk yolks with 3/4 cup of sugar on medium speed until creamy and the sugar is completely dissolved, about 2-3 minutes. Add vanilla* and stir to combine. Turn the speed down to low and slowly add oil. Then alternately add dry ingredients and 1/2 cup water and stir just until combined. Begin and end with dry ingredients. Set aside.
With a handheld or stand mixer fitted with a whisk attachment whisk egg whites until soft peaks form. Add 1/2 cup sugar and mix until stiff peaks form. Using a wooden spoon, gently fold egg whites into egg yolks. Divide batter into two bowls equally. Add cocoa to one of the two bowls and carefully fold in just until combined. Alternately spoon light and bright batter into prepared bundt pan. Bake for 60-65 minutes until the bundt cake bounces back to touch. Let cool in the bundt pan for 1 hour. Then invert the pan onto a wire rack and let cool completely. Store in an airtight container at room temperature for up to 3 days.
*First, cut off the straight end of the vanilla bean. Then place the tip of your sharp knife below the curled end and cut the vanilla bean through the middle of the bean lengthwise. Although you don't need to cut it all the way through, it's ok when you do so. Then open the vanilla bean and scrape out the flavorful seeds with the back of your knife. Then just use the seeds.