Melt the butter in a small pan.
When melted, add the saffron, and allow the mixture to cook for a couple of minutes.
Remove from the heat, and stir in the milk and dried yeast. Allow to sit for five minutes or so.
Add the cooled mixture and the egg to your stand mixer, and give it a quick mix.
Add the sugar, salt and 300g of flour.
Work the mixture, gradually adding as much flour as necessary (one tablespoon at a time). Make sure you work each tablespoon in before adding more. Be careful with this step, as too much flour will result in dry bread.
You will hear your mixer laboring a little harder as the dough becomes thicker (mine clanks about a bit). The dough will be tacky, but you will be able to easily pull it off the attachment. When this happens, switch to a dough hook, and knead for a further five minutes.
When ready, the dough should be shiny, and drop fairly easily from the hook.
Cover with a tea-towel and allow the dough to proof for 1-2 hours (just until doubled in size).
When the dough is ready, grease a large springform pan (mine is 23cm / 9").
Pre-heat the oven to 200℃ / 400℉.
Knock back the dough and divide into three.
Roll out into long ropes measuring about 50cm / 19" each.
Place the top of the ropes (furthest away from you) on top of each other and press down.
Plait / braid the dough. Start by taking the left hand rope and placing it over the middle. Then do the same with the right hand rope. Continue down to the bottom. Keep it fairly tight, but don't create too much tension. Press the ends of the ropes together, just as you did at the start.
Pull both ends of the plaited dough together to form a wreath, with one end slightly overlapping the other.
Place inside the baking pan. Cover and leave to rest for 30 minutes.
When ready, bake in the lower part of the oven for around 20 minutes.
Remove and allow to cool for a while, remove the springform edge, and leave to cool completely.