Preheat your oven to 375°F (190°C) and line a muffin tin with paper liners or grease well.
In a large mixing bowl, whisk together the flour, sugar, and baking powder until evenly combined. This creates a light, airy base for your muffins.
In a separate bowl, pour in the melted butter, then add the eggs and vanilla extract. Whisk until the mixture is smooth, fragrant, and slightly thickened.
Pour the wet mixture into the bowl with the dry ingredients. Gently fold everything together with a spatula just until combined; do not overmix to keep the muffins tender.
Carefully fold in the blueberries, distributing them evenly throughout the batter. If using frozen berries, toss them in a little flour beforehand to prevent sinking.
Divide the batter evenly among the muffin cups, filling each about three-quarters full. This ensures even baking and a nice risen top.
Bake the muffins in the preheated oven for 20-25 minutes, or until the tops turn a golden brown and a toothpick inserted in the center comes out clean.
Remove the muffins from the oven and let them cool in the tin for about 5 minutes. Then transfer them to a cooling rack to cool slightly and set the crumb.
Enjoy your muffins warm or at room temperature, perhaps with a pat of butter or a drizzle of honey for extra indulgence.
