In a small saucepan, warm the milk to around 95-104°F / 35-40°C and pour it into the bowl of a stand mixer. Sprinkle yeast and sugar over the milk. If using active dry yeast, let this sit for around 5-10 minutes until it becomes foamy; if using instant yeast, this step can be skipped.

Add the flour, salt, and eggs to the milk mixture. Fit the stand mixer with a dough hook attachment and mix on low speed until a thick dough forms.

Add in the softened butter, a few cubes at a time, and keep mixing on medium speed for around 10 minutes until the sweet roll dough pulls cleanly from the sides of the bowl and is soft and strong.

Alternatively, knead the dough by hand. Use a wooden spoon and mix the dough until it forms a shaggy ball. Pull it onto a floured surface and knead in the butter, a few cubes at a time. Knead by hand for around 10 minutes until it becomes an elastic and smooth dough. If you need a break, take it. The dough responds well to resting time.

Once kneaded, form the dough into a dough ball. Transfer the dough to a lightly greased large bowl and cover it with plastic wrap or a damp dish towel.

Let the dough rise in a warm place until doubled in size, around 1 to 1 ½ hours. The total time will depend on your room temperature. If your room is cold, you can create a warm spot for rising by placing the dough in a turned-off oven next to a mug of boiled water.

The dough can be covered tightly and refrigerated for up to 16 hours if you make overnight blueberry cinnamon rolls.

While the dough rises, make the filling so it has time to chill before using it.

Add the blueberries, cornstarch, sugar, cinnamon, lemon juice, lemon zest, and salt to a saucepan over low heat. Keep stirring until they begin to break down.

Once they have broken down and released their juices, turn the stove to medium heat and let the mixture boil, stirring for around 4-5 minutes. As the mixture boils, it will thicken and become jelly-like. Make sure to keep stirring so it doesn't burn.

Once thick, remove it from the heat, scrape it into a bowl, and let it cool to room temperature. Cover it and place it in the fridge until it's needed.

Grease or line a 9x13-inch baking dish with parchment paper.

Punch down the risen dough, then pull it from the bowl onto a lightly floured surface. Dust the top of the dough with some flour.

If the dough has come from the fridge, it will be very stiff. Let it warm up to room temperature for 10 minutes before rolling.

Use a rolling pin to roll the dough into a large rectangle measuring around 12x16 inches (30cmx40cm).

Dollop the cold blueberry mixture over the dough, but keep aside two tablespoons for the frosting. An offset spatula spreads the blueberries out, leaving a 1-inch border.

Carefully roll the dough up from the longest side into a log. Cut the log into 12 equal pieces using unflavored dental floss or a serrated knife.

Place the rolls into the prepared pan. Cover the pan and let the rolls rise in a warm spot until doubled in size.

Preheat the oven to 350°F /180°C.

Bake the rolls in the oven for around 25-28 minutes until deep golden brown. If they are browning too fast, you can cover the top of the rolls loosely with aluminum foil.

While the rolls are baking, make the frosting. In a large bowl, using a handheld or stand mixer fitted with a whisk or paddle attachment, beat the cream cheese and butter together on high speed until smooth and creamy.

Add in the confectioners sugar, vanilla, and salt. Beat on low speed to incorporate the powdered sugar, then switch to high and beat until creamy.

Dollop in the reserved blueberry filling and swirl it in to create some streaks.

Let the baked buns cool for 20 minutes, then spread on the frosting.