Over a very low heat, melt the dark chocolate then stir in the orange extract.
Gently heat the coconut milk until bubbles start to form at the sides, then pour it over the chocolate mixture. Leave to sit for 5 minutes then mix together until smooth.
Transfer mixture into a small baking dish and place in the fridge for 45 minutes.
Scoop the chilled mixture out, 1 tablespoon at a time, and roll into small balls. Place in the freezer for 5 minutes while you prepare the white chocolate.
Gently melt the white chocolate in a pan then dip each truffle until covered. Place in the fridge for 1 hour to set.
If desired, melt dark chocolate and drizzle a little over each truffle. Refrigerate until the drizzle hardens before enjoying.