1. Roughly chop the chilli and add to the milk (with the seeds) and bring the milk to the boil. For a less intense chilli flavour, remove the seeds from the chilli before chopping. Allow milk to infuse for at least an hour, but better if overnight.
2. Once infused, strain out the chilli from the milk. Add more milk if required to ensure 100ml. Boil the milk once again.
3. Melt the chocolate in a heatproof bowl over simmering water (do not allow the bowl to touch the surface of the water.)
4. Add the boiled milk to the melted chocolate. Remove from the heat and whisk to combine. Set aside to cool slightly. Add the egg yolk and whisk to combine.
5. Beat the egg whites with a mixer. When soft peaks form, add the sugar slowly and continue to whisk until the egg whites are firm and glossy.
6. Take about 25% of the egg whites and temper into the chocolate mixture by whisking. Then add the chocolate mixture into the egg whites and slowly fold together until combined
7. Pour into four individual, long stemmed serving glasses and place in the refrigerator to set for at least an hour. Garnish with grated chocolate and serve your chilli chocolate mousse.