1. Warm the milk to lukewarm (36-40C (97-104F). It should feel warm to touch, not hot. Add the yeast, sugar and salt. Leave until slightly foamy and yeast has started to activate.
2. In a stand mixer with dough hook, combine flour, egg, buttermilk, and yeast mixture. Mix for 4 to 5 minutes (or kneed by hand if you aren’t using a mixer) until dough starts to come together and is smoother.
3. Add the softened butter and continue mixing (kneading) for about 5 to 10 minutes until the dough is smooth, soft and slightly sticky to the touch. It should feel sticky but not stick to your fingers aggressively. If the consistency is not right, add a bit more flour or water/milk.
4. Place the dough into a lightly butter greased bowl, cover and leave somewhere warm for around 1 to 2 hours or until doubled in size.
   
Time to rise will depend on the conditions in your kitchen. Dough likes a warm slightly humid environment to rise.

Filling

1. Mix together the softened butter, brown sugar and cinnamon.
2. Roll the dough onto a lightly floured surface and roll into a rectangle, roughly 40 x 30 cm and 0.5 to 0.7cm thick
   
3. Spread the filling evenly over the dough as close to the edges as possible
4. Roll the dough tightly from the long edge into a log
5. Slice the rolls into 10-12 evenly sized rolls and place into the prepared baking dish (refer base layer below for preparing the baking dish).

Base Layer

1. Mix the softened butter, Vegemite, sugar and heavy cream.
2. Spread the filling evenly over a ceramic or glass baking dish (approximately 9 x 13 inch/ 23 x 33cm)

Second Rise

1. Cover the rolls loosely and leave in a warm humid place to rise until puffed up and soft.
   
At this step, can place these in the fridge overnight if you want to have these in the morning without having to get up at 3 am! Or leave overnight if you have a cool kitchen. They will need to come to room temp before baking if leaving in the fridge.

Bake

1. Preheat the oven to 180 C (350 F) and bake the buns for approximately 30 minutes.
If the tops are darkening too quickly, cover with foil. Always check the dough is fully cooked through using a knife to test on the inner most bun.

Frosting

1. While the buns or cooling or while they are cooking if the patience has completely gone out the window, start preparing the frosting
2. Mix together the softened butter and cream cheese (room temperature is best) in a stand mixer or using hand held mixer, until light and fluffy.
3. Add the icing sugar, vanilla, lemon and salt and mix until smooth well combined. Taste and adjust with more sugar if not sweet enough for your taste.
4. Once the buns are cool to the touch but still warm, spread frosting over the top. If you prefer a firmer frosting, wait for the buns to cool completely before frosting