Place roux ingredients into the Thermomix bowl and cook 3 min/80°C/speed 3. Cool slightly. Leave in the Thermomix bowl.
Add flour, cacao, salt, butter, buttermilk, zests, oils spices and yeast and mix 10 sec/speed 6. Knead 3 min/Interval.
Add chocolate and knead 1 min/Interval.
Scrape out onto floured silpat mat and wrap into a tight ball. Prove until doubled.
Shape into buns with well floured hands. 120g per bun.
Place onto a lined baking tray, cover and rise until doubled.
Meanwhile, make a paste for the crosses by placing all ingredients into the Thermomix bowl and mixing 20 sec/speed 6. Scrape and repeat. Pipe crosses onto each bun.
Place into a cold oven set to 180°C and bake for 25-30 minutes. Using a cold oven produces another little rise for your dough.
To make the glaze, place all ingredients into a saucepan and heat until the sugar has dissolved.
When you remove them from the oven, brush generously with the glaze.
Serve warm with lots of butter.