1. Preheat oven to 325 Degree Fahrenheit. Grease and flour 9 x3 spring-form pan. Make sure it has a tight fitting bottom to prevent the batter from leaking
2. Sift together the flour, baking powder, baking soda and salt into a medium bowl
3. In the bowl of an electric mixer, beat the butter at medium speed until creamy, about 1 minute. Gradually add the sugar and beat at high speed until the mixture is pale and well blended, about 3 minutes. Add the cocoa powder and beat at medium speed for 1 minute, scraping down the sides of the bowl as necessary. Beat in the eggs one at a time, beating well after each addition. Beat in vanilla extract. At low speed, add the flour mixture in three additions alternating it with the warm water in two additions. Scrape down the sides of the bowl and mix at low speed for 30 seconds. Pour the batter into the prepared pan and smooth the top.
4. Bake the cake for 45 to 55 minutes. Check cake with tester to make sure it comes out clean (toothpick or skewer is fine). Cool the cake in the pan on a wire rack for 20 minutes
5. Remove the side of the pan and invert the cake onto the rack. Remove the bottom of the pan and let the cake cool completely.
6. Store at room temperature, wrapped in foil, for up to 5 days.