Preheat your oven to 375 degrees. Spray an 8 inch round cake pan with cooking spray, and press some parchment paper into it, forming it to the inside of the pan- it doesn't have to be perfect, little paper ridges will make the cake wavy and cute on the outside.

In a large bowl, add in all the ingredients for the cake batter- the softened butter, vegetable oil, sugar, vanilla extract, eggs, sour cream, milk, flour, salt, baking powder, and cornmeal. This is a bit of an odd method, but bear with me- just beat everything together until it's well combined and a thick batter forms.

Pour the batter into your prepared cake pan and spread it evenly. Evenly sprinkle the blueberries all over the top of the cake- it should cover most of the top of the cake. Generously sprinkle the coarse sugar over the top evenly. Bake the cake for 28-30 minutes, or until the cake looks lightly golden brown on top, and a cake tester comes out with just a few crumbs clinging to it. Let the cake cool completely in the pan, and use the parchment paper to remove the cake. Slice and serve!