Mix dry ingredients separately. Toss blueberries with 1 tbsp flour. Prepare batter by creaming butter and sugar, then add eggs and vanilla. Fold in sour cream, dry ingredients, and blueberries. Pour into pan, sprinkle with sugar, and bake at 350°F (175°C) for 35-40 minutes.
Notes
Use fresh blueberries for best flavor, but frozen work well too.