Pre-heat oven to 350°F Spray the bottom and sides of a 8x8 inch glass or ceramic baking dish with parchment. For metal baking pans, heat oven to 325degF.

In a bowl, combine flour, sugar, cocoa, baking powder, baking soda and salt.

Mix in the egg, milk, oil and vanilla. Continue mixing on low speed until well combined. Mix until well combined. Increase speed to medium and continue mixing for 2 minutes.

Stir in warm water. The batter will become very thin.

Place batter in prepared dish. Bake for 35-40 minutes or until a toothpick is inserted and the batter is crumbs-free. You don't want to have wet batter. However, a few crumbs are good.

Allow the pan to cool for 10 minutes, and then let it cool on a rack.

Heat the chocolate chips in a microwave-safe medium bowl for 30 seconds at 50% power. Stir after each heating until the chocolate is melted completely.

Mix the vanilla with the sour cream until it is smooth and fluffy.

Spread the spread on top of the cooled cake.