Preheat the oven to 350F degrees. Grease and flour a 9x13 inch cake pan.
Sift together the flour, baking powder, baking soda and salt in a medium bowl.
In a large bowl beat together the butter and sugar until fluffy.
Add in the vanilla extract, then beat in the eggs 1 at a time.
In a liquid measuring cup or small bowl whisk together the milk and sour cream.
Then carefully beat about ⅓ of the flour mixture into the butter mixture, followed by about ⅓ of the milk and sour cream mixture. Repeat the process with the rest of the flour mixture and sour cream mixture adding about ⅓ of each at a time.
Gently fold in the chopped berries using a spatula or wooden spoon.
Pour the batter into the prepared pan and bake for 27-33 minutes or until an inserted toothpick comes out clean.
Allow to cool.