Preheat your oven to 375°F (190°C) and line a muffin tin with paper liners or grease it well.
In a large mixing bowl, whisk together the flour, baking powder, and salt until evenly combined. This creates a light, airy base for the batter.
In a separate bowl, melt the butter gently in the microwave or on the stovetop, then let it cool slightly. Whisk in the sugar until the mixture looks smooth and slightly glossy.
Add the eggs one at a time to the butter-sugar mixture, whisking well after each addition. The mixture should become creamy and slightly thickened.
Pour in the buttermilk and gently whisk until the batter is smooth. It will be thick but pourable—this is perfect.
Carefully fold the blueberries into the batter, using a spatula to keep the berries whole and avoid crushing them. The batter will be thick and speckled with fruit.
Spoon the batter evenly into the prepared muffin tin, filling each cup about three-quarters full. Gently press a few extra blueberries on top of each muffin for a burst of color and flavor.
Sprinkle a pinch of coarse sugar over each muffin for a crunchy, sweet topping that crackles as they bake.
Bake in the oven for 20-25 minutes, until the muffins are golden brown, fragrant, and a toothpick inserted into the center comes out clean.
Remove the muffins from the oven and let them rest in the tin for about 5 minutes. Then transfer them to a wire rack to cool slightly.
Serve these warm or at room temperature, ideally within a day or two for the best flavor and moisture. Enjoy their tender crumb and juicy blueberry bursts!
