Combine softened butter and sugar in a mixing bowl. Using an electric mixer, mix the ingredients until light and fluffy.
Add the eggs and continue mixing for 3-5 minutes until the mixture is light and creamy.
Add the vanilla and mix briefly to incorporate.
Add the flour, baking soda, and baking powder and mix until just combined. Do not over-mix!
Finally, add the sour cream and mix until smooth. Again, do not over-mix!
Pour half the cake batter into the prepared pan and use a rubber spatula to flatten it into an even layer.