Preheat your oven to 350°F (175°C) and grease a 9x13 inch baking pan with butter or cooking spray, then dust it with flour.

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

In a large bowl, cream the softened butter with granulated and brown sugars until light and fluffy. Beat for about 3-5 minutes.

Add the eggs one at a time, ensuring each is fully blended before adding the next. Stir in the vanilla extract.

Alternate adding the dry mixture and sour cream to the butter mixture, mixing until just combined.

Pour the batter into the prepared pan and smooth the top. Bake for 30-35 minutes, rotating halfway through.

Once baked, cool in the pan for 10 minutes before transferring to a wire rack to cool completely.