Preheat the oven to 350 degrees. Spray a donut pan with non stick spray, then set aside.
In a medium bowl whisk together the flour, baking powder, baking soda, salt and cinnamon. Then set aside the flour mixture.
2 ¼ cups (281 g) all-purpose flour, spooned and leveled, 1 ½ teaspoon baking powder, ¼ teaspoon baking soda, ½ teaspoon salt, 1 tablespoon ground cinnamon
In a large bowl, cream the butter, white sugar and brown sugar together with an electric mixer on high speed until fluffy, about 2 minutes.
10 tablespoon (140 g) unsalted butter, softened, ¾ cup (150 g) granulated white sugar, ¾ cup (165 g) light brown sugar
Add in the eggs and vanilla and mix on medium high speed until pale in color and fluffy, about 1 minute.
2 eggs, at room temperature, 1 teaspoon vanilla
Add in the sour cream and buttermilk and combine on low speed.
¾ cup (180 ml) buttermilk, at room temperature, ¾ cup (184 g) sour cream, at room temperature
Add the dry ingredients to the wet ingredients and mix on low speed until all is combined.
Add the donut batter to a piping bag. Pipe the batter into the greased donut pan until each well is a little more than ¾ full.
Bake for 12-14 minutes, until the edges are a light golden brown.
Let the donuts cool in the pan for 2 minutes, then turn them out onto a cooling rack to cool completely.