Preheat the oven to 350 degrees.
Line an 8x8 glass or ceramic baking dish with parchment paper. Set aside.
Cream the butter and cane sugar together in a bowl. Add the egg and whisk well.
In a separate bowl, combine the all purpose flour, baking soda, and salt. Whisk until well combined.
Next, you will pour the rest of the liquid ingredients into the creamed butter and sugar mixture. This includes, vanilla flavor, milk, and vegetable oil. Whisk until well combined.
Then, add the dry ingredients to the wet ingredients and whisk until a batter forms.
Gently fold in the fresh blueberries using a spatula. This will prevent them from breaking.
Pour the batter into the prepared baking dish.
Spread the batter evenly and bake for 43-44 minutes or until fully cooked through.
Cut into squares and enjoy!