In a mixing bowl, combine flour, yeast, sugar, and salt. In a separate bowl, whisk together warm milk, melted butter, and egg. Pour the wet ingredients into the dry ingredients and mix until a dough forms.

Knead the dough on a floured surface for about 5 minutes until smooth. Place in a greased bowl, cover, and let rise in a warm place for 1 hour or until doubled in size.

In a small bowl, mix together the brown sugar, cinnamon, and softened butter until well combined.

Once the dough has risen, roll it out on a floured surface into a rectangle about 1/4 inch thick. Spread the cinnamon filling evenly over the dough, then sprinkle the blueberries on top.

Starting from one edge, roll the dough tightly into a log. Cut into 8 equal pieces and place them in a greased baking sheet.

Preheat the oven to 350°F (175°C). Let the rolls rise for another 30 minutes. Bake for 25 minutes or until golden brown.

In a bowl, whisk together powdered sugar, milk, and vanilla extract until smooth. Drizzle over the warm rolls before serving.