Preheat oven to 350 degrees. Cream together the butter and sugars until lightened in color and fluffy. Add the eggs, one at a time, and mix well after each addition. Mix in the vanilla. In a separate bowl, combine the flour, baking powder, and baking soda. Whisk together until the flours and leavening agents are incorporated with each other.
Add the sour cream and flour mixture in alternating amounts, mixing between additions until combined.
Place 1/2 of batter into a 9" cake pan with high sides (at least 2" inch) that's been prepared with baking spray. Sprinkle 1 1/2 cups chocolate chips over the batter, and then top with the remaining batter and spread over to cover.
In a separate bowl, whisk together the cinnamon and brown sugar, and then sprinkle over the top of the cake.
Bake for 45-50 minutes, or until a cake tester comes out with moist crumbs.
To finish cake, melt your remaining chocolate chips over a double boiler or following the package directions and drizzle over the cake.