Preheat the oven to 350°F. Spray two muffin tins with nonstick spray or line the muffin cups with paper liners.

In a large bowl, whisk together 3 cups flour, 1 tablespoon baking powder, and 2 cups granulated white sugar.

Add 1/2 cup (1 stick) butter, cut into pieces, to the dry mixture. Use a pastry blender (or two knives) to cut the butter into the dry ingredients until the mixture is crumbly and resembles coarse crumbs.

Reserve 1 cup of the crumbly mixture in a small bowl and set it aside for the topping.

To the remaining crumb mixture in the large bowl, add 2 large eggs, 1 cup milk, and 1 teaspoon vanilla extract. Use an electric mixer on medium speed and beat until the batter is smooth and combined.

Gently fold 1¾ cups fresh blueberries into the batter with a rubber spatula, mixing just until the berries are evenly distributed.

Scoop the batter into the prepared muffin cups, filling each about three-quarters full.

Stir 2 tablespoons melted butter into the reserved 1 cup crumb mixture just until moistened and slightly clumpy; then sprinkle this topping evenly over the batter in each muffin cup.

Bake for 20 to 25 minutes, until a toothpick inserted into the center of a muffin comes out clean or with a few moist crumbs.

Remove the muffins from the oven, let them cool in the pans for about 5 minutes, then transfer to a wire rack to cool.