1. PREHEAT oven to 350°F.
2. Line two 8” OR 9” round cake pans with parchment paper rounds and lightly spray the paper and any exposed parts of the pans with baking oil.
3. Whisk together all-purpose flour, GODIVA Dark Chocolate Hot Cocoa Mix, baking soda and salt in a medium bowl; set aside.
4. Put the sour cream in a small microwave-safe bowl. Microwave in 10-second intervals, stirring in between, until the sour cream is slightly warmed, but not hot to the touch when tasted; set aside.
5. Place the finely chopped GODIVA Large 72% Dark Chocolate into a small microwave-safe bowl. Microwave on medium (50% to 60% power) for 1 minute. Stir. Continue heating in 30-second intervals until the chocolate is almost completely melted, but some small chunks remain. Stir until smooth; set aside.
6. In the bowl of a stand mixer, beat the butter for 1 minute, or until smooth. Add dark brown sugar and continue to beat on medium high for 3 minutes, or until smooth and fluffy; scraping sides occasionally. Drizzle in vegetable oil and continue to beat for 3 minutes, scraping sides as needed.
7. Add the egg and vanilla extract and beat for 30 seconds or until well mixed; scrape sides.
8. Drizzle in the cooled, melted chocolate and continue beating on medium high until thoroughly blended and smooth, scraping sides occasionally.
9. With the machine off, add one third of the flour mixture and slowly bring the mixer to medium speed. Continue to beat until well mixed (about 10 seconds), scraping the sides. Drizzle in about half of the very hot water. Add remaining flour mixture in two more additions, alternating with the very hot water (starting and ending with the flour mixture), and scraping sides often.
10. Add the slightly warmed sour cream and mix on low just until mostly blended. Remove bowl from the mixer, scrape the sides, and continue to fold in the sour cream by hand, using a rubber scraper, until well incorporated. Divide evenly between the two prepared pans. Smooth tops and bake for 30-35 minutes, or until toothpick inserted into center comes out clean.
11. Cool cakes in pans on racks for about 20 to 25 minutes, then carefully invert onto racks, and remove pans to cool completely before assembly (about 2 hours). Unfrosted, cooled cakes can be made in advance, stored in an airtight container with parchment between the layers, and refrigerated up to one day or frozen up to 2 weeks before assembly.
12. Mix Ganache Frosting (recipe below) about 1 hour before assembling the cake.