Prepare Your Pan: Preheat your oven to 425°F / 220°C. Generously grease 11 cups (2640 ml) of a standard muffin tin with butter, making sure to grease the top flat surface of the pan as well, since the muffins will bake over the edge.
Combine Dry : In a large bowl, whisk together the whole wheat pastry flour, sugar, baking powder, and salt.
Add the blueberries (do not thaw if frozen) and gently toss to coat them in the flour mixture. This prevents them from sinking to the bottom.
Mix Wet : In a separate medium bowl, beat the eggs, then whisk in the milk and vanilla extract.
Combine Wet and Dry: Pour the wet into the dry . Gently fold them together with a spatula just until the flour is moistened.
Do not overmix! A few lumps are perfectly fine.
Add Butter: Drizzle the melted butter into the batter and mix a few more times, just until it's incorporated.
Fill and Top: Divide the batter evenly among the 11 prepared muffin cups. The batter should fill each cup to the very top.
Sprinkle a generous amount of sugar over the top of each muffin.
Bake to Perfection: Bake for 15-18 minutes, or until the tops are golden brown and a toothpick inserted into the center of a muffin comes out clean.
Cool and Enjoy: Let the muffins cool in the pan on a wire rack for 10 minutes before carefully removing them. For an extra sparkly finish, you can sprinkle them with a little more sugar right out of the oven.
Serve warm!
Do not overmix the batter.
Mix only until the are just combined. Overmixing develops gluten and results in tough, dense muffins instead of light and fluffy ones.