Toss fresh blueberries in a tablespoon of flour before folding them into the batter to prevent them from sinking to the bottom during baking and ensure even distribution throughout.

Use room temperature eggs and buttermilk to create a smoother, more homogeneous batter that incorporates air better, resulting in fluffier, lighter doughnuts.

Mix dry and wet ingredients until just combined—overmixing activates gluten and creates tough, dense doughnuts instead of the desired tender crumb.

Reserve some batter to pipe on top of blueberries placed in the doughnut cavities, which keeps berries suspended in the center rather than clustering at the bottom.

Apply powdered sugar glaze or coating within 2-3 minutes of removing doughnuts from the oven while they're still warm, allowing it to adhere beautifully and create a delicate, even coating.