Preheat the oven properly – Set your oven to 375°F (190°C). Line a muffin tin with paper liners or grease lightly.

Soak the bran – In a bowl, combine wheat bran and buttermilk. Let it sit for 10 minutes. This softens the bran and prevents dryness.

Mix wet ingredients – In another bowl, whisk melted butter and brown sugar until smooth. Add eggs one at a time, then stir in vanilla extract.

Combine dry ingredients – In a separate bowl, whisk flour, baking soda, baking powder, and salt to distribute evenly.

Bring the batter together – Add the soaked bran mixture to the wet ingredients. Gradually fold in the dry ingredients until just combined. Avoid overmixing.

Prepare blueberries – Toss blueberries lightly in 1 tablespoon of flour to prevent sinking.

Fold in blueberries gently – Add coated blueberries to the batter and fold carefully to avoid crushing them.

Fill muffin cups evenly – Divide batter evenly among muffin cups, filling about ¾ full.

Bake until golden – Bake for 20–25 minutes, or until a toothpick inserted in the center comes out clean.

Cool before serving – Let muffins rest in the tin for 5 minutes, then transfer to a cooling rack.