Requires: 4 dariole moulds (or ramekins), food processor (for the walnut crumb)
Soak the gelatine leaves in a small bowl of cold water for 5–10 minutes or until softened. Set out the dariole moulds (or ramekins).
Heat half of the cream, sugar and coffee into a small heavy-based saucepan over low-medium heat. Bring almost to boiling point, then remove from the heat. Squeeze out the excess moisture from the soaked gelatine leaves. Stir the soaked gelatine leaves into the hot cream and coffee mixture until well combined and the gelatine is completely dissolved. Set aside to cool slightly.
Whip the remaining cream until soft peaks form. Fold the whipped cream into the cream and coffee mixture. Pour the coffee-flavoured panna cotta mixture through a sieve into a jug, then pour into dariole moulds (or ramekins). Refrigerate for 4 hours or until set.
Note: You can prepare the panna cotta in advance and refrigerate overnight.
Tip: Rinse the dariole moulds (or ramekins) in cold water (without drying them) before pouring in the panna cotta mixture. This will make the panna cotta easier to turn out once set.
Preheat the oven to 180°C conventional oven/ 160°C fan-forced (350° Fahrenheit/Gas 4). Line a shallow baking tray with baking paper.
To make the walnut crumb, place the flour, caster sugar, butter and walnuts into a food processor. Process until mixture becomes a coarse crumb. Spread the walnut crumb mixture onto the prepared baking tray. Bake for 5 minutes or until lightly golden. Remove from the oven and set aside to cool, then break up into small pieces.
To serve, dip the dariole moulds (or ramekins) in boiling water for 7 seconds. Turn each coffee-flavoured panna cotta onto a serving plate. Arrange the walnut crumb on top of the panna cotta – buon appetito.