Preheat the oven to 350 degrees and spray a 9x13 with pam baking spray.
Using a medium bowl, whisk together the flour, baking powder, and salt.
Using a large bowl, beat the butter and sugar together until creamy and combined.
Beat in the eggs, and vanilla until combined.
Beat in the sour cream until combined.
Alternating between the dry ingredients and the buttermilk, gradually beat in the two ingredients until combined.
Fold in 2 1/2 C of the blueberries into the batter.
Scoop the batter into the pan.
Top the batter with an even layer of the crumble.
Sprinkle remaining raspberries on top of the crumble.
Place into the oven and bake for 50-60 minutes or until a toothpick comes out clean.
Place the cake onto the counter and allow it to cool completely
Enjoy!