Preheat oven to 350 degrees. Butter a 9'' cake pan and dust with flour; set aside.
Make chocolate syrup: In a small sauce-pan melt all the ingredients for the Chocolate Chunk Syrup (1-2 minutes), stirring occasionally.
In a large bowl, Mix together flour, sugar, cocoa, baking soda, baking powder, and salt in a stand mixer using low speed until combined. Add egg, milk, water, oil, and vanilla. Beat on medium speed until smooth. Pour batter into greased and floured cake pan.
Scoop in the chocolate chunk syrup mixture and swirl with a knife until the mixture is fully incorporated. Bake for 30 minutes, until a cake a toothpick inserted, comes out clean. Cool in the pan for 10-15 minutes then drizzle with ganache.
To make Ganache: While the cake is baking, Bring cream just to a boil over medium-high heat. Pour over chocolate, and add salt. Let stand for 10 minutes (don't stir -- doing so will cool the ganache too quickly, making it grainy). After 10 minutes Stir with a whisk until smooth and shiny to break up any pieces and emulsify cream and chocolate. Chocolate will often settle on the bottom or sides of the bowl. Scrape dish with a rubber spatula to incorporate all of it. Let cool for at least 3-5 minutes and no more than 15 minutes before Pouring on the cooled cake.