If you haven’t already, melt the butter and allow it to come to room temperature, and remove the milk and eggs from the fridge.
Preheat oven to 350°F and line two 8” cake pans with parchment paper, and spray with nonstick spray.
In a medium bowl, add the sugar and lemon zest, then use your fingers to rub them together, which will release the lemon flavor.
To that same bowl, add the flour, baking powder, baking soda, and salt and stir to combine.
In a large bowl, whisk the butter, milk, eggs, vanilla and lemon juice together, then pour the dry ingredients into the set and whisk together with a hand mixer, being careful not to over-mix. Fold in the blueberries with a rubber spatula.
Pour the batter evenly into the prepared cake pans. Place the cake in the oven and bake for 35-40 minutes or until a toothpick comes out clean. Leave the cakes in the pans for 10 minutes, then invert onto a cooling rack. Allow the cakes to cool completely before icing them.
For the icing: Add all ingredients to a bowl and whisk together with a hand mixer until the icing is smooth.
Dollop a large amount of icing on top of one of the cakes and spread it around, then place the second cake on top and repeat the process until the cake is coated in icing. Slice and enjoy!