Preheat the oven to 350° and grease a muffin pan with some baking spray.
How To Get Seeds Out Vanilla Pod:
Place the bean on the cutting board and carefully slice through it, lengthwise, to split the bean. Use the dull side of the knife or a butter knife to scrape the beans out of the inside of the pod.
In a large mixing bowl, whisk egg, sugar, melted butter, vanilla seeds, and buttermilk.
Sift in flour, salt, baking powder, and baking soda. Whisk together until smooth.
Fold in blueberries.
Fill the muffin pan cups 3/4 full with muffin batter and bake for 30-35 minutes.(Do a toothpick test around 30 minutes to check if they are done. Tip: insert the toothpick in the batter part and try not to hit the blueberry.)
Disclaimer: Nutrition information shown is not guaranteed to be 100% accurate as most ingredients and brands have a slight variation.