In a small bowl, dissolve the yeast in warm milk with a pinch of sugar. Let it stand for about 5 minutes until it becomes foamy.

In a large mixing bowl, combine the flour, sugar, and salt.

Add the softened butter, egg, and the yeast mixture to the dry ingredients. Mix until the dough forms.

Knead the dough on a floured surface for 8-10 minutes until it is smooth and elastic.

Place the dough in a greased bowl, cover it, and let it rise in a warm place for about 1 hour, or until it has doubled in size.

While the dough is rising, beat the cream cheese, powdered sugar, and vanilla extract until smooth and creamy.

In a small saucepan, combine the blueberries, cornstarch, and water. Cook over medium heat until the mixture thickens, about 5 minutes. Let it cool.

Once the dough has risen, roll it out into a 12x16 inch rectangle.

Spread the cream cheese filling evenly over the dough, then spoon the blueberry mixture over it in dollops.

Carefully roll up the dough from the long side into a tight log.

Cut the log into 12 equal slices and place them cut side up in a greased 9x13 inch baking dish.

Cover and let the rolls rise for another 30 minutes.

Preheat the oven to 350°F (175°C).

Bake the rolls for 25-30 minutes, or until they are golden brown and cooked through.

Let cool slightly before serving.