Preheat your oven to 350F. Grease three 8-inch round cake pans and line them with parchment paper.

In a large bowl, whisk together the flour, sugar, cornstarch, baking powder, baking soda, and salt.

Using an electric mixer, add the butter one tablespoon at a time until the mixture becomes sandy in texture.

Slowly drizzle in the oil while mixing until fully incorporated.

In another bowl, whisk together the buttermilk, lemon zest, lemon juice, eggs, and vanilla extract.

Slowly drizzle the buttermilk mixture into the butter mixture, mixing until well combined.

Gently fold the blueberries into the batter.

Divide the batter evenly among the prepared pans and bake for 30 minutes or until a toothpick inserted into the center comes out clean.

Let the cakes cool in the pans for 10 to 15 minutes, then transfer to a cooling rack.

Once cooled, frost with lemon frosting or your preferred frosting.