Combine brandy and blueberries in a small bowl. Cover and set aside until required.
Preheat oven to 160C/140C fan-forced.
Heat cream, milk and salt in a small saucepan over medium heat until just boiling. Remove from heat. Add chocolate and stir until smooth and combined.
Meanwhile, whisk sugar, yolks, vanilla and cocoa powder in medium heatproof bowl until combined. Whisk in chocolate mixture until combined. Pour mixture into four, ¾ cup (180ml) capacity oven-proof dishes.
Place dishes in a baking dish. Pour boiling water into baking dish until halfway up the sides of smaller dishes. Bake for 35-40 minutes or until just set. Remove dishes from oven and water bath. Set aside to cool to room temperature. Cover and refrigerate overnight (or up to 2 days).
Drain blueberries (if all the alcohol hasn’t been absorbed). Top chocolate creams with a little whipped cream, blueberries and hazelnuts. Serve.
Remove chocolate creams from refrigerator 30 minutes before serving.