In a large bowl, sift the cake flour. Then, whisk in the granulated sugar, light brown sugar, baking powder, baking soda, kosher salt, and ground cinnamon. Lastly, add in the blueberries and carefully mix to distribute. In a small bowl, combine 1 tablespoon of granulated sugar with ¼ teaspoon of ground cinnamon. Set aside.
2 ½ (312 g) cups Cake flour, 2 ½ teaspoons Baking powder, ½ teaspoon Baking soda, ¾ teaspoon Ground cinnamon, ½ teaspoon Kosher salt, 1 (200 g) cup Granulated sugar, ¼ (55 g) cup Light brown sugar, 2 cups Fresh blueberries, 1 tablespoon Granulated sugar, ¼ teaspoon Ground cinnamon
In a medium bowl, whisk together the eggs and sour cream until smooth. Then mix in the vanilla extract, melted butter, oil, and buttermilk.
¼ (60 g) cup Sour cream, 2 large Eggs, ¼ (57g) cup Unsalted butter, ¼ (56 g) cup Vegetable oil, 1 tablespoon Vanilla extract, 1 (240 g) cup Buttermilk
Pour the wet ingredients into the dry ingredients and gently mix them together with a rubber spatula until just combined. Don't worry if the batter looks a little lumpy, it's expected.
Cover the bowl with plastic wrap and and allow the batter to rest for 1 hour. After 1 hour, preheat the oven to 425F. Line a cupcake or muffin pan with 6 paper liners, placing each liner in every other cup. (For this method, you will bake the muffins in two batches. Be sure to cover the batter while the first batch bakes. Alternatively, you can bake all 11 at one time but your muffins won't be as tall.)
Using an ice cream scoop, gently scoop the fluffy muffin batter into the paper liners, taking extra care not to deflate the batter. Overfill each liner to the top.
Top each batter filled muffin liner with a sprinkle a generous sprinkle of cinnamon sugar and extra blueberries.
Bake at 425F for 5 minutes. Then, (without opening the oven door), lower the oven temperature to 375F and bake for an additional 15 - 18 minutes or until the muffins are golden brown and a toothpick inserted into the center comes out clean.
Allow the muffins to cool in the pan on a wire rack for 10 minutes. Then, transfer the muffins to a cooling rack. (You may need to use a small butterknife to get in between the muffin tops and the cupcake pan as the berries may stick to the pan). Allow muffins to cool for an additional 10 minutes, then enjoy!!