Preheat the oven to 425 degrees F. Line 2 baking sheets with parchment.
Cream together the butter and granulated sugar in an electric mixer. Add the egg and beat well. Set aside 1 tablespoon of the flour for the blueberries, then add the remaining flour to the butter mixture and mix until combined.
In a separate bowl, dissolve the baking soda in the buttermilk. Add the buttermilk mixture to the batter along with the orange zest and mix well.
Toss the reserved 1 tablespoon flour with the blueberries in a bowl. Using a spatula, fold the blueberry mixture into the batter until combined.
Use a standard ice cream scoop (1/4 cup) to scoop out the dough onto the lined baking sheets, spacing the scoops 2 to 3 inches apart. Bake until lightly browned, about 11 minutes. Transfer the muffin tops to a rack set over a baking sheet to cool completely.
In a small bowl, combine the confectioners' sugar and orange juice and mix well. Drizzle the glaze over the cooled muffin tops and let set.