Put the cream and vanilla pod in an enamel or stainless steel saucepan and bring very gently to a simmer, stirring occasionally to prevent scorching.
Put the egg yolks, vanilla essence and sugar in a large bowl. Using a hand-held mixer beat for 4-5 minutes until thick, pale and a ribbon is left when the mixture is trailed back over itself. Remove the vanilla pod and slowly mix small batches of the hot cream into the yolks.
Add the marula fruit liqueur, coffee liqueur and coffee extract.
Preheat the oven to 170C/150C Fan/Gas 3.
Strain the flavoured custard and then divide equally between 6 ramekins. Place the ramekins in a deep roasting tin and add enough just boiled water to reach halfway up the sides of the ramekins.
Bake for 45 minutes, or until set but with a slight wobble. Cool thoroughly and chill in the fridge, then clean carefully round the edges.
For the sugar crust, preheat the grill to its highest setting. Sprinkle a teaspoon of sugar over each crème brûlée and put them under the grill until the sugar melts and caramelises. Alternatively use a chef’s blowtorch to caramelise the sugar. Serve once the caramel has hardened.