01 -
Preheat oven to 175°C (350°F) and grease a donut pan with non-stick spray or melted butter.
02 -
In a large mixing bowl, whisk together flour, sugar, baking powder, baking soda, salt, and cinnamon until thoroughly combined.
03 -
In a separate bowl, whisk buttermilk, melted butter, egg, and vanilla extract until smooth and well incorporated.
04 -
Pour the wet ingredients into the dry ingredients and stir gently until just combined. Avoid overmixing to maintain a light texture.
05 -
Gently fold in the blueberries, being careful to minimize breaking them, especially if using frozen berries.
06 -
Transfer the batter to a piping bag or use a spoon to fill each donut cavity approximately 3/4 full.
07 -
Bake in the preheated oven for 12-15 minutes, until edges turn golden brown and a toothpick inserted into the center comes out clean.
08 -
Allow donuts to cool in the pan for 5 minutes before transferring to a wire rack to cool completely. Dust with powdered sugar if desired before serving.