
Make the blueberry filling by cooking blueberries, sugar, cornstarch, zest, juice, and extract in a pot until thickened.
Prepare the dough by combining sugar, lemon zest, warm milk, yeast, egg, yolk, and butter in a bowl and mixing well.
Knead the dough until smooth and let it rise until doubled in size.
Roll out the dough, spread the blueberry filling, and roll it tightly before cutting into slices.
Place the rolls in a baking dish, let them rise, then bake until golden.
Prepare the frosting and spread it over the warm rolls before serving.