Preheat the oven to 375 degrees. Line a 24 count mini muffin pan with mini muffin papers.
In a bowl, combine the flour and the baking powder.
Using a stand mixer or hand mixer, beat the butter and sugar together until light and creamy.
Add the eggs one at a time and mix well. Scrape down the sides of the bowl with a spatula.
Add the vanilla and the flour, mix on low speed until combined and then add the milk.
Mix until the batter is smooth.
Add the blueberries and mix.
Using a spoon scoop up some of the batter and drop it carefully into each muffin paper, enough to be level with the top.
Place the pan into the oven and bake for about 17-20 minutes and the muffins are slightly golden brown on top.
Let cool for 5 minutes before transferring to a wire rack.
Keep stored in a ziplock bag or freeze and rewarm in the microwave for 5-8 seconds per muffin.