Line a baking sheet with parchment paper.
Place the cream and chocolate in a medium bowl and place over a pan of barely simmering water.
Stir until the chocolate has melted and the mixture is smooth, which takes about six minutes.
Stir in the tarragon, wine and salt until smooth.
Refrigerate for two hours until firm.
Let the mixture stand at room temperature until moldable, which takes about 45 minutes.
Using a melon scoop, scoop level amounts of the truffle mixture on to the prepared baking sheet.
Roll into 1/2-inch balls.
Place the cocoa powder in a small bowl.
Roll the truffles in the cocoa powder until coated.
Arrange on a platter and serve or refrigerate in an airtight container.