Preheat oven to 350.
Prepare two 8" round pans with cooking spray and line the bottoms with parchment paper.
In a small bowl, sift the flour, baking powder, baking soda, and salt. Set aside.
In a medium saucepan combine the sugar with 2 cups of water, bring to a boil over high heat and stir until the sugar dissolves.
Pour into a large bowl and then add the chocolate and butter.
Let sit for a few minutes then stir until melted and slightly cooled.
Stir in the vanilla.
Beat the eggs into the chocolate mixture at medium speed.
Add the flour mixture all at once and continue beating on medium until smooth.
Pour the batter into the two pans.
Bake for 25 minutes or until a cake tester comes out clean.
Let cool in pans for 25 minutes, then remove from pans and cool completely.