1. Preheat your oven to 350°F 180°C and grease a 9×13 inch baking pan with nonstick spray or butter; line with parchment paper for easier removal if you like.

2. In a large bowl whisk together the all-purpose flour granulated sugar baking powder baking soda and salt until well combined.

3. In a separate bowl whisk the milk sour cream eggs melted butter and vanilla extract until smooth and fully blended.

4. Pour the wet mixture into the dry ingredients and stir gently with a spatula just until no dry streaks of flour remain being careful not to overmix the batter.

5. Spread the batter evenly into the prepared pan smoothing the top so the cake bakes uniformly and the cinnamon swirl can sit on a level surface.

6. In a small bowl stir together the melted butter light brown sugar ground cinnamon salt and vanilla for the cinnamon swirl until thick glossy and evenly mixed.

7. Spoon the cinnamon mixture in small dollops all over the surface of the batter then use a butter knife to gently swirl it through the cake in loose figure eights without fully blending it in.

8. Bake the cake for 28 to 33 minutes or until the top is lightly golden the edges just begin to pull away from the pan and a toothpick inserted in the center comes out with a few moist crumbs.

9. Place the pan on a wire rack and let the cake cool for at least 20 minutes so it is warm but not hot before frosting.

10. For the frosting beat the softened cream cheese and softened butter together in a medium bowl until smooth and creamy with no lumps remaining.

11. Add the powdered sugar vanilla salt and 2 tablespoons of cream or milk then beat until light fluffy and spreadable adding an extra tablespoon of cream if needed to loosen.

12. Spread the cream cheese frosting evenly over the warm cake allowing it to melt slightly into the swirls then slice into squares and serve warm or at room temperature.