1. Preheat the oven to 350°. Grease an 8-inch square baking pan and set aside.

2. In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set dry ingredients aside.

3. Using an electric mixer, cream together the butter and 1 cup sugar until fluffy, about 5 minutes. Add in the eggs, one at a time, beat until smooth. Beat in the sour cream and vanilla extract. Mix until well combined.

4. Slowly add in the dry ingredients. Mix until just combined. In a small bowl, make the cinnamon sugar topping/filling. Stir together sugar, brown sugar, and cinnamon. Pour half the batter into the prepared cake pan and sprinkle with half the cinnamon-sugar and half the chocolate chips. Spoon the remaining batter over the filling, spreading gently. Sprinkle with the remaining cinnamon-sugar and chocolate chips.

5. Bake until golden and a toothpick inserted in the center comes out clean, about 40 minutes. Cool to room temperature and serve.