Whip the room temperature butter and sugar. Add the egg and vanilla extract and whip to a smooth consistency.
Mix the dry ingredients together and add to the butter mix. Do not whip too much but just enough to get everything mixed together.
You can add a thin layer of oil to your cake pan if you want to. Add the batter and spread it evenly with your hand. You can have some flour on your fingers to keep them from sticking.
Mix the starch with your blueberries. Add them as an even layer on your base. (If you want you can save some berries as decoration on top. )
Mix the sour cream, egg, sugar, and vanilla together. Spread it on top of the blueberries as an even layer.
Bake at 350 F for around 40 minutes until the edges have some color. The top can have some brown spots, they taste delicious, a bit caramelly.
Let the pie cool down before serving. The middle is wobbly when you take it yout from the oven but it sets when cooled.