Preheat oven to 375ºF. Prepare a 12-cup muffin tin by lining with papers or greasing well.
Pour boiling water over wheat bran in a large bowl and stir until absorbed. Stir in brown sugar, vegetable oil and egg.
In a separate bowl, whisk together flour, baking powder and salt. Add to bran mixture, gently stirring until mostly combined (there should still be a few floury streaks). Fold in blueberries, then divide batter among muffin cups. Bake 15-20 minutes, until tops feel springy when gently pressed. Transfer to wire racks to cool.