Open 10 cardamom pods, crushing the insides with a pestle and mortar and add to a saucepan.
Add the milk plus 50g of the butter (leaving the rest of the butter at room temperature until required).
Gently warm the milk, stirring so it doesn't catch, until it's steaming but not boiling. Remove from the heat and leave to cool until lukewarm, making sure the butter has melted into the mixture.
Put the flour, 75g of the sugar, the yeast, cinnamon and 1/2 tsp salt into a large bowl, or the bowl of a freestanding mixer and mix until combined.
Pour the cooled milk mixture through a sieve into the flour mixture, this will remove the cardamom.
Using a dough hook or wooden spoon mix to form a soft dough, then turn out onto a very lightly floured surface.
Knead for 10 minutes until it's smooth and stretchy. You could do this using the dough hook for 5-7 minutes, but I always find I get better results if I do it by hand.
Clean out and lightly oil the mixing bowl, transfer the smooth ball of dough into it and cover with a tea towel before leaving to rise for 2 hours, or until doubled in size (you could leave it in the fridge overnight if you wanted).
Crush the remaining cardamom seeds with the mortar and pestle and combine them with the remaining 150g of sugar.
Mix the remaining room temperature butter with all but 2tbsp of the cardamom sugar.
Line two baking sheets with greaseproof paper in preparation for the buns.
Punch the dough down to knock out the air and turn out onto a flat surface.
Roll out into a rectangle of 35x45cm with one of the longer edges facing you.
Cover the whole thing with the cardamom butter, spreading it as evenly as possible, right up to the edges.
Fold the top third down to the middle and the bottom third up over that, so you have one long piece with 3 equal layers of dough.
Cut in to 12 equal strips (about 3.5cm wide).
Making sure you leave it attached at the top, cut each strip down the centre so it has two tentacles.
Now for the tricky bit. Follow the instructions above, but in summary: Twist each strip away from the centre two or three times, then tie the dough in a knot and tuck the ends underneath the bun.
Place each finished knot onto the prepared trays when you're done.
Lightly oil some clingfilm and cover the trays, leaving them to prove for another 30 minutes to an hour, until they've doubled in size again.
Preheat your oven to 190°C (170°C fan assisted).
Remove the clingfilm, brush each bun with the beaten egg and sprinkle with the peal sugar.
Place in the middle of your preheated oven and bake for 20-25 minutes. You may want to swap the trays around half way through. They should come out golden brown.
Once they are out and cooling, tip the remaining cardamom sugar into a saucepan with 50ml of water and bring to the boil.
Remove from the heat to cool and brush over the buns 2-3 times while they are cooling.
Leave the buns 20 minutes to soak up the sugar syrup and serve warm. They'll keep a couple of days in a sealed container.