This is a recipe I got from an old friend of mine. Not sure where she got it but it's hand written on a large index card in my personal cookbook. She has since passed, so I'm sorry I don't know where it originated.
I've made it many times and my family just loves it. I hope you enjoy it too.
Cream butter and sugar, then add eggs and beat well. In a separate bowl blend flour, baking powder, baking soda, and salt. Alternately add the flour mixture with the sour cream, beginning and ending with flour. Stir in vanilla. Gently fold in 1 cup of blueberries that have been coated with a little flour.
Grease 13" X 9" pan, I use Bakers Joy, pour in half of the cake batter, then cover with the remaining blueberries that have been coated with a little flour, then add the remaining cake batter.
Bake at 325 degrees --45 to 50 minutes or until it tests done.