Coating blueberries with flour before folding them into the batter serves two purposes. u003cbr/u003eu003cbr/u003eFirst, it helps prevent the blueberries from sinking to the bottom of the cake during baking. The flour coating provides a bit of u0022grip,u0022 helping the berries stay suspended throughout the batter for a more even distribution. u003cbr/u003eu003cbr/u003eSecond, it helps absorb excess moisture from the blueberries, preventing them from releasing too much liquid into the batter, which could affect the cake's texture and consistency.u003cbr/u003e