Preheat oven to 350°F (175°C). Grease and flour a 9x13 inch baking pan.
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.
In a large bowl, beat the softened butter and sugar together until light and fluffy.
Beat in the eggs one at a time, then stir in the vanilla extract.
In a small bowl, whisk together the sour cream (or yogurt) and milk.
Gradually add the dry ingredients to the wet ingredients, alternating with the sour cream mixture, mixing until just combined.
Gently fold in the frozen blueberries.
Pour the batter into the prepared baking pan and spread evenly.
Bake for 35-40 minutes, or until a wooden skewer inserted into the center comes out clean.
Let the cake cool in the pan for 10-15 minutes before slicing and serving.