Count out 20 cardamom seeds.
Grind the seeds either in a pestle and mortar or a spice grinder
Weigh out 200g of the soya/oat milk into a medium pan.
Add in the ground cardamom seeds and ground cinnamon.
Bring almost to the boil and stir well then leave to steep as it cools. Or if in a hurry, you can simmer it gently for a few minutes.
Allow to cool thoroughly - put in the fridge or freezer if you want to hurry it up. If in the freezer set a timer so you don't forget about it!
Pour the mango pulp into a 2 litre jug or other container.
Pour the yogurt (500g) into the same jug.
Once the infused soya milk has cooled strain into the jug. Make sure to use a very fine strainer or the lassi will have a very gritty unpleasant texture. It's easiest to do it through a course strainer first, then use a fine one.
Add in the rest of the oat milk (300g) & the coconut milk if using.
Mix all ingredients and blend well with a stick blender or electric whisk.
Return to fridge to allow the flavours to integrate and to chill it down.
Serve with a straw!