Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9x13 inch pan.
In a large bowl, beat eggs until light and fluffy. Gradually beat in sugar, oil and vanilla. Beat in cocoa, flour, baking powder and salt. Stir in warm water. Pour batter into prepared pan.
Bake for 30 to 40 minutes in the preheated oven, or until top is springy to the touch and a toothpick inserted into the center comes out clean. Allow to cool before serving.
Interesting Facts
This cake is called 'magic' because it is made with one batter that separates into three layers during baking – a moist chocolate cake layer, a creamy custard-like layer and a fudgy top layer.
The cocoa powder gives this cake its dark chocolate flavor. You can use any type of cocoa powder, such as Dutch-processed, natural cocoa powder, or a combination of both.
This cake is best served at room temperature. It can be stored in an airtight container at room temperature for up to 3 days.