Preheat your oven to 375°F (190°C). Line a muffin tin with paper liners.

In a large bowl, combine the bran cereal and buttermilk. Let it sit for about 5 minutes to soften the bran.

Stir in the honey, vegetable oil, eggs, and vanilla extract until well combined.

In a separate bowl, whisk together the flour, baking powder, baking soda, and salt.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Gently fold in the blueberries.

Divide the batter equally among the muffin cups, filling each about 2/3 full.

Bake for 18-20 minutes, or until a toothpick inserted into the center of a muffin comes out clean.

Remove from the oven and let the muffins cool in the tin for 5 minutes before transferring them to a wire rack to cool completely.