In a bowl, mix together milk and vinegar and set aside for 10 minutes. It will curdle. Your buttermilk is ready.
In a larger bowl, mix together wheat flour, salt, sugar and instant yeast.
Make a well in the center and add buttermilk.
With a spoon, roughly mix the flour to incorporate the liquid. At this stage, the dough may seem a bit dry — but after you add the butter, the consistency will change.
Now add the butter and mix until it is incorporated into the dough. The dough will become very sticky.
Dust two tablespoons of flour on the counter and transfer dough to the counter.
Start kneading. Do not be tempted to add more flour. Keep on kneading for 3-4 minutes. Use a dough scraper to make kneading easier.
Oil a clean bowl, place the dough in it and coat the top of the dough with oil. Cover with cling wrap and set aside until it doubles in volume.
Once your dough has doubled in size, transfer dough to counter and press it to release the gas bubbles.
Divide it into 6 equal portions.
Roll each portion into a tight ball and place on a greased baking tray. Cover and set aside for 15 minutes.
By the time the buns are proving, preheat oven to 200°C. Meanwhile, mix the honey and milk.
Apply a coat of this milk to the buns. Sprinkle sesame seeds on top.
Place it in preheated oven and bake for 20 minutes in the middle rack.
Remove the brioche buns from the oven, and allow it to cool on a wire rack for 10 minutes.
Let it cool completely on the wire rack.