Preheat the oven to 350F (180C) and grease the bottom of 9x13 inch pan.
In a medium bowl mix the flour, baking powder, baking soda and salt. Measure the sour cream in a separate bowl and mix in the vanilla extract.
Cream the butter and sugar until it is light and fluffy, about 3-4 minutes. Scrape the bottom and sides of the bowl.
Add the eggs, one at a time, waiting for each egg to fully incorporate before adding the next.
Scrape the bottom and sides of the bowl.
Reduce mixer speed to low, then add the flour mixture to the butter mixture in three additions alternating with the sour cream mixture. Starting and ending with the flour mixture.
Once you added the last portion of the flour, use a rubber spatula to incorporate dry flour residues.
Pour the cake batter into the prepared pan and bake for 38-42 minutes.
Remove from the oven and allow the cake to cool completely before assembling.