Preheat oven to 425 degrees. Combine Kodiak Cakes mix, milk, and eggs in a bowl and mix until smooth.
Spray a half baking sheet pan with non-stick spray then line with parchment paper (optional).
Pour batter into sheet pan, spreading with a rubber spatula, if necessary. Drop blueberries into batter.
Bake for 10-12 minutes or until golden brown and springy to the touch. If unsure, insert a toothpick into the center. It should come out clean. Cut into 12 squares while warm. Allow to cool for about 15 minutes before removing from sheet pan.