Put the raw cocoa nibs and 1 cinnamon stick in a pan and roast gently for 3 mins over a low-medium heat (this is to intensify the flavour). The nibs will begin to release a chocolate aroma.

Transfer the nibs to a mortar and pestle. Grate the tonka bean (or scrape out the vanilla seeds) into the mortar. Add the nutmeg, bay leaves and a pinch of salt to the mortar and crush to a fine texture. Alternatively, use a blender.

The resulting cocoa will be dry in texture (it needs to be softened to mould), so transfer it to a bowl and microwave (medium heat, not high) for 1-2 mins. It should become warm and pliable.

Sift a thick dusting of cocoa powder onto a chopping board or counter. Divide the cocoa into 4 equal portions. Put a dusting of cocoa powder in your hand, then take a portion of the mixture and begin to mould into a ball. Repeat with the remaining 3 portions.

Dust the balls with extra cocoa powder and leave in a cool place (or refrigerate) to harden completely.

To make three cups of tea, put 4 cups of water into a pot along with the lemongrass, bay leaves and remaining cinnamon stick. Bring to a roaring boil, then lower the heat to simmer.

Grate 1 of the cocoa balls into a separate bowl, then transfer it to the pot of boiling water. Be careful, as it can foam and spill over the rim. Stir and allow the cocoa to dissolve, this should take around 3 mins.

Make the cornstarch slurry by mixing the cornstarch with 2 tbsp of water.

Increase to a medium heat and pour in the whole milk and condensed milk (to taste – some like it sweeter than others). Remove from the heat. Slowly whisk the cornstarch slurry into the liquid, whisking continuously to prevent lumps.

Sieve the tea before serving and finish with a cinnamon stick in each mug.