In a large bowl, combine warm milk, yeast, and 1 tablespoon of the sugar. Let stand for 5-10 minutes until foamy, which means the yeast is active.

In a small saucepan over medium heat, combine blueberries, 1/3 cup sugar, cornstarch, and lemon juice. Simmer for 6-8 minutes, stirring frequently and mashing berries with a spoon, until mixture thickens to a jam-like consistency. Remove from heat and let cool completely.

Add remaining sugar, melted butter, egg, and salt to the yeast mixture. Stir in flour one cup at a time until a soft dough forms. Knead on a floured surface for 5-7 minutes until smooth and elastic, or use a stand mixer with dough hook for 4-5 minutes.

Place dough in a greased bowl, cover with a damp towel, and let rise in a warm place for 1-1.5 hours until doubled in size.

Punch down the dough and roll into a 15x12-inch rectangle on a floured surface. Brush the entire surface with 3 tablespoons melted butter, leaving a 1/2-inch border on one long edge.

Mix brown sugar and cinnamon together, then sprinkle evenly over the buttered dough. Dollop the cooled blueberry mixture over the cinnamon sugar and gently spread it, leaving some areas with just cinnamon showing for visual swirl effect.

Starting from the long edge opposite the border, tightly roll the dough into a log. Pinch the seam to seal. Using a sharp knife or dental floss, cut into 12 equal slices.

Arrange rolls cut-side up in a greased 9x13-inch baking pan, spacing them about 1/2 inch apart. Cover with a towel and let rise for 30-45 minutes until puffy and touching each other.

Preheat oven to 350°F. Bake rolls for 25-30 minutes until golden brown on top and the internal temperature reaches 190°F. The edges should be lightly golden and the centers set but soft.

While rolls cool slightly, whisk together powdered sugar and 2 tablespoons milk, adding more milk if needed to reach a thick but pourable consistency. Drizzle glaze generously over warm rolls and serve immediately.