Warm milk to around 37C (you don't want it to be cold, but not too warm either). Add the milk and sugar to the bowl of your stand mixer and mix until the sugar is dissolved. I use the whisk attachment for this step.

Now add the sourdough starter, flour and eggs to the bowl. Mix into a rough dough and let it sit for around 30 minutes. I use the dough hook attachment for this step and all subsequent kneading.

Once the dough has sat for a little while, add the butter and salt and use the stand mixer to knead it really well. You want the butter to mix all the way through and the dough to become very soft and elastic.Depending on the type of mixer you use, this could take 3 minutes, it could take 20 minutes.

Once the dough is silky and elastic (it can be slightly sticky) it should be pulling away from the sides of the bowl, it's time to add the chocolate chips and ensure they are mixed through the dough evenly. Transfer the dough into a large bowl for bulk fermentation. Cover with plastic and set aside.

Once the dough has risen a bit (it doesn't have to double, 50% rise is ok in this instance) you'll need to shape the brioche dough.

Turn the dough onto the counter and divide into equally weighted balls of dough.

You can choose to shape as a loaf or into individual rolls. Brioche Rolls - If making rolls I generally make 12 rolls weighing 100g each and bake them in an 8" x 12" pan.Loaf - If making a sandwich loaf I divide dough into reasonably equal pieces and form into 4 balls. Place the balls into a loaf pan (I use a 1.5 pound USA pan).

Once shaped, allow the dough to proof and get nice and puffy. This can take quite a while due to the butter, milk and eggs.

Once the dough is puffy, it's time to bake! Preheat your oven to 180C/350F.

While the oven is preheating, mix an egg with 1 tablespoon of water and brush the dough generously with this egg wash.

Bake the sourdough brioche at 180C/350F for around 20-25 minutes for rolls and 30-35 minutes for a loaf.

Once the loaf or rolls are out of the oven, brush with lashings of butter while still in the pan. Cool on a wire rack.