Preheat oven to 350 F. Spray a Bundt pan with flour-added baking spray.
Mix together flour, sugar, cocoa, soda, baking powder and salt in large bowl. Add oil, milk, eggs and vanilla. Beat two minutes with electric mixer at medium speed. Stir in water until blended. Batter will be thin.
Pour batter in the Bundt pan and bake for 45-50 minutes or until skewer or pick inserted comes out clean.
Let the cake sit in the pan for about 10 minutes, then carefully turn it from the Bundt.
We like to make the ganache in large microwave-safe measuring cups. Feel free to use a saucepan and bowls if you prefer.
In one 2 cup microwave-safe measure (or bowl), combine the chopped chocolate, corn syrup and butter.
In a second microwave-safe measure, heat the cream just until it begins simmering. This should only take 30-60 seconds depending on your microwave.
Gradually stir the hot cream into the chocolate mixture. It will go from thin to thick, thin to thick and might seem to thin at first. It thickens as it cools. However, if it does seem to thin to you as you add the cream you can add less.
Stir until very smooth. Let cool slightly if it's still seems thin, then drizzle over the cake.