In a large bowl, whisk together the warm milk, yeast, and 1/2 tsp sugar and let it rest until fluffy for 5-7 min.

In a large bowl (preferably of a stand mixer), add the flour, the remaining sugar, salt, eggs, butter, vanilla, and the activated yeast. Mix them well until combined for about 3-4 minutes. Then, cover it with a cloth or plastic wrap and let it rest at room temperature for 4-5 minutes.

After the dough has rested, knead the dough with a stand mixer or using your hands for 8-10 mins. Then transfer the dough into a large bowl, cover with plastic wrap, and let it sit for 40-45 minutes until doubled in size. After the initial proof, place it in the refrigerator and let it rest for another 1 1/2 hours.

In a medium bowl, mix the butter, sugar, cinnamon, instant coffee, salt, and vanilla.

Place the dough onto a lightly floured surface and roll the dough into a 10x14 rectangle (around 1/4 inch thick). Evenly spread the filling over the dough. Starting from the long end, roll the dough down to the bottom edge until you have one long roll. Using a string or sharp knife, cut the dough into 8-9 equal rolls.

In a cast iron or baking dish, spread butter and light brown sugar on the bottom of the pan. Place the buns on the prepared dish and cover it with a clean kitchen towel. Let it rest for 40-45 min at room temp.

Preheat the oven to 350F.

In a small bowl, combine 1/3 cup heavy cream and 1 tbsp instant coffee. Uncover the rolls and pour the coffee and cream mixture over them. Bake the rolls for about 25-30 minutes or until golden. Remove them from the oven and let them cool for 10 min.

In a medium bowl, beat together the mascarpone, powdered sugar, heavy whipping cream, and salt until fully combined. Spread the frosting on the rolls while they are still warm. Using a sifter or mesh strainer, dust the tops of the rolls with cocoa powder.

Serve with a cup of coffee and some fresh fruit, if desired.

Bon appetit!