Preheat oven to 325F, grease the bottom of 3-8" round pans, and grease the sides. Set aside.
In a large bowl, sift together the cake flour, ap flour, baking powder, baking soda, and cinnamon. Use a fork to mix and blend. Set aside.
In a bowl of a standing mixer, beat the butter with the sugars medium speed until well combined about 2 minutes.
Reduce speed to low and drizzle in the oil, increase speed back to medium and mix until light in color and fluffy, about 4 minutes. Stop the mixer halfway and scrape the bottom and sides of the bowl.
Reduce speed to low and add the eggs one at a time, waiting for each egg to fully incorporate before adding the next. Do the same with the egg yolks.
Turn mixer off and scrape the sides and bottom of the bowl.
Back at low speed add the flour mix in 3 additions alternating with the sour cream starting and ending with the flour.
Once you added the last portion of the flour mix, turn the mixer off and use a rubber spatula to fully incorporate the flour.
Divide the batter between the greased pans (approx. 400 g each) and flatten it using an offset spatula.
Using a spoon, dot the batter with the blueberry cinnamon filling then gently swirl the batter with the filling.
Bake for 35-40 minutes or until a toothpick comes out clean from the center of the cakes.
Remove cakes from the oven and allow to cool before completely filling and frosting the cakes.