Preheat your oven to 350 degrees Fahrenheit and grease 3, 9-inch round cake pans and line the bottom of the cakes with parchment paper for easy release after baking.
Using a stand mixer, beat the butter on high until creamy. Then, add in the granulated and brown sugar and beat together until creamed.
Next, add in the vanilla and eggs and beat until everything is combined. Scrape down the bowl as needed.
In a separate bowl, combine the flour, baking powder, and salt. Then, slowly add the dry ingredients into the mixer with the wet ingredients.
After combined, add in the buttermilk, lemon zest, and lemon juice until just combined.
On the side, combine the blueberries with 2 teaspoons of flour and then gently fold them into the batter. Be sure to not over mix your batter.
Spoon the batter evenly into the 3 cake pans and bake for 20-25 minutes until a toothpick comes out clean.
While the cakes are baking, prepare the frosting. Using a stand mixer, beat the cream cheese and butter together until no lumps remain.
Next, add in the confectioner's sugar, heavy cream, vanilla and salt and beat until all is combined together smoothly.
To assemble the cake, place one layer on your cake stand or plate and then using a very thin amount of icing, cover the top with the cream cheese frosting. Repeat this step for the next layer as well. Finally, add the top layer (if it is not even you can use a serrated knife to level it out) and coat the top and sides with the remaining cream cheese frosting.
Then, decorate to your liking and then chill in the fridge for 45 minutes before cutting or the cake may fall apart.
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Notes
When the cake has fully cooked it will be a light color and not golden brown so keep this in mind so you don't over cook your cake layers!