Preheat your oven to 350 degrees.

Spray two 8 inch round cake pans with nonstick spray and set aside.

In a large bowl, whisk together cake mix plus ingredients on the back of the box.

Add in lemon zest and the juice of 1 lemon, and mix well.

In a separate bowl, add the flour, and toss the blueberries into the flour. This can help keep the blueberries from sinking.

Shake off the excess flour and add the blueberries to the cake mix, and gently fold them in.

Pour batter evenly between the cake pans.

Bake at 350 according to the time on the box, but also adding 2-3 extra minutes since we added the blueberries.

A toothpick inserted in the center should come out clean (minus blueberry) when the cake is finished baking.

Allow the cake to cool completely before frosting.

To make the frosting, in a large bowl use a hand mixer to mix together softened butter and powdered sugar until well incorporated.

Add vanilla, milk, and 1 tbsp. lemon juice, mix well until frosting forms and is well combined.

If the frosting is too thick, add milk, 1 tbsp. at a time, until it reaches the desired consistency.

Frost your bottom layer of your cake, set the top layer on, and frost again, then top with fresh lemon slices and fresh blueberries.