Preheat your oven temperature to 400°F. Grab a muffin tin (12-cup or similar) and line it with cute paper liners.
Mix the baking powder, flour, and salt in a bowl. Set it aside for a second.
Take another small bowl and toss the blueberries in with about one tablespoon of our dry mixture from Step 2.
In a larger bowl, beat unsalted butter, sugar, and eggs until fluffy (2 minutes, medium speed). Add the vanilla extract and stir again.
Gradually add a third of our dry ingredients (from Step 2) to the wet mixture (Step 4), mixing it all up. Alternate adding milk and your remaining dry ingredients until everything is nicely combined.
Gently fold the flour-coated blueberries (from Step 3) into the batter, then divide it evenly among the paper liners in your muffin tin. Optional: Sprinkle more berries on top (or a bit of streusel or coarse sugar).
Bake them for around 20 minutes. They're ready when the tops turn a lovely golden brown. Also, the toothpick poked into the middle should come out mostly clean with very few wet crumbs.
Let them sit in their tins for 4-5 minutes before transferring them to a rack to chill completely. Enjoy!