Preheat oven to 350F and line two baking sheets with parchment paper.
In the bowl of your stand mixer (or using a hand mixer), add the butter and 6 tablespoons of sugar and beat for 1 minute. Add the egg and vanilla and mix to combine.
Add the baking soda, baking powder, salt, flour and milk and mix to combine, scraping down the sides to ensure everything is incorporated. Remove from the bowl from the stand mixer.
Gently fold in blueberries into the batter using a spatula.
Using a cookie scoop, place 6 heaping scoops on each baking sheet, leaving at least 1 1/2 inches of space in between scoops as the muffin tops will spread quite a bit when baked.
Bake in the oven for approximately 17-18 minutes. Let cool for 10 minutes before removing them from the baking sheet.
Note: Metric ingredient measurements are provided as a courtesy using a third-party calculator and are rounded to the nearest unit. The recipes provided on this site have not been tested with metric measurements and their accuracy cannot be verified.
The nutritional information provided is based on third-party calculations and is an estimate only. Accurate nutritional facts will vary based on the particular brands used, portion sizes, measurement accuracy and more.