In one bowl combine the flour, baking powder and salt.
In a large bowl with mixer at medium speed cream the softened butter and sugar until light and fluffy.
Add in the eggs one at a time beating after each addition. Add the flour mixture and the milk and vanilla - alternating after each addition.
Crush 1/2 cup of blueberries and fold into the batter. Fold in the remaining whole blueberries.
Lightly grease and flour two 8 inch cake pans. Line bottoms with parchment paper.
Evenly divide the batter between the two pans and spread evenly.
Top each layer with the crumble. (Recipe above)
Bake in a preheated 375 degree oven for 30-35 minutes.
Test with a toothpick and if the toothpick comes out clean they are done.
Allow pans to cool for 10 minutes in pans, then remove and place on cooling rack and allow to
cool for another 30 minutes.
for the frosting
In a large bowl, beat together the butter and cream cheese with an electric mixer. With the mixer on low speed, add the powdered sugar a cup at a time until smooth and creamy.
Beat in the vanilla extract and the lemon juice.
Fold in lemon zest
When cake layers are cool, spread frosting on top of bottom layer. Stack second layer on top of bottom layer and frost sides of cake. Garnish with additional lemon zest and blueberries if desired.
Notes
To help prevent your berries from sinking while the cake bakes, lightly roll them in flour.