Melt the butter in a large glass bowl in the microwave.
Stir in sugar with a sturdy spatula or wooden spoon.
Add eggs, milk and sour cream. Stir to combine thoroughly.
Stir in wheat bran.
Add vanilla, baking soda, baking powder and cinnamon.
Add all purpose flour. Stir until muffin mixture is well combined.
Add in blueberries and gently stir into muffin batter.
Using a large muffin scoop, scoop muffin batter into muffin tins with paper liners. (Paper muffin liners are necessary for this recipe, rather than greasing the tins, so the blueberry juice is contained a bit more.) Fill muffin cups until 2/3 full.
Bake at 350 degrees for 25 to 30 minutes.
Cool muffins on a wire rack and enjoy! Store cooled muffins in an airtight containers. Store at room temperature for a day or two, or freeze cooled muffins to enjoy later.