Simmer cream and milk in a heavy-bottomed pan.
Stir in sugar until completely dissolved.
Add vanilla seeds and pod, then remove from heat to infuse for five minutes.
Soak gelatine in cold water for 4 minutes, squeeze out excess, and dissolve into the hot cream.
Stir in coffee granules, strain through a sieve into a jug, and discard vanilla pods.
Pour mixture into six moulds and refrigerate for three hours until set.
Boil 50ml of water in a pan.
Whisk in chocolate and remaining water over low heat until a smooth sauce forms.
Loosen panna cottas by dipping mould bases in hot water.
Turn out onto plates and serve with chocolate sauce and amaretti biscuits.