To make the poolish, mix the zopf flour, milk and fresh yeast in a bowl or big glass jar. I use a 500ml Weck glass jar for it. Close it with the lid or a plastic wrap and leave it to sit at room temperature for 5 hours. Your poolish will rise to at least double the size, so make sure to use a jar which is big enough.

After 4 hours, take out the milk and butter from the fridge and let it warm to room temperature (1 hour is a suitable time).

Add the poolish, zopf flour, milk, fresh yeast, salt and lemon zest to your kitchen machine and knead at the lowest possible speed for 5 minutes.

Turn the speed level one up and knead for another 5 minutes.

Add the butter, piece by piece, until well combined with the dough. This will take you about 5-10 minutes.

Add the sugar and bourbon vanilla sugar and mix for another 5 minutes until the sugar is combined with the dough.

Cover the bowl with a damp kitchen towel and let it rise for 2 hours at room temperature.

After 2 hours, your dough should have doubled in its size. Place it on a well-floured working surface and cut away six pieces of about 80g. The remaining part is for the middle.

Form all pieces into round balls. The easiest way is to fold the outside of the dough into the middle, turn it upside down and form a ball with your hands. Don't forget to place a little king or an almond in one of the balls.

On a baking paper, place the biggest ball into the middle and lay the other 6 pieces around it. Put it on a large plate, cover with a damp kitchen towel and leave it in your fridge overnight. Your dough will now slowly rise overnight.

The next morning, preheat your oven to 190°C/350°F (conventional). It will take up to one hour till your entire oven reaches this temperature.

At the same time, take your dough out of the fridge, mix one egg with a tablespoon of milk in a small bowl and brush your dough with it. Leave it at room temperature until your oven is preheated.

Brush your dough again with the egg-milk-mixture and sprinkle with coarse sugar.