Toss the blueberries with 3 tablespoons of the sugar and set aside.

Grease 12 muffin cups or spray with baking spray.

In a large bowl, combine the flour, the remaining sugar, salt, and baking powder. Whisk to blend.

In a small bowl, whisk the milk with the eggs and vanilla extract. Add the milk and egg mixture to the dry ingredients along with the melted butter. Mix just until the ingredients are moistened.

Spoon the batter into the prepared muffin cups—about 1/3 to 1/2 cup in each muffin cup—and sprinkle with cinnamon-sugar, if desired.

Bake the muffins until browned and a toothpick inserted into the center of a muffin comes out clean or with just a few crumbs.

Let the muffins cool for 10 to 15 minutes, then turn them out of the pan and continue cooling on a rack.

In a small bowl, combine 1/4 cup of room temperature unsalted butter, confectioners' sugar, honey, 3/4 teaspoon of cinnamon, and a pinch of salt.

Beat or whisk the butter until it is well blended and fluffy.

Serve alongside the muffins.