In a large mixing bowl, break up the chocolate and add the salt. Set aside.
Heat the sugar on a low-medium heat until melted and starting to turn amber.
Remove from the heat then add the vanilla extract, coconut oil and water. Return the pan to a gentle heat and warm it up for a few minutes. Don’t worry if the sugar solidifies, just keep stirring it on a low heat until it dissolves again.
Pour the heated liquid straight onto the chocolate and hand whisk continuously until the chocolate has melted and the mixture is smooth.
Pour half the chocolate mixture over the base, then pour in the raspberry layer but leave about 1cm around the edge. Pour the other half of the chocolate over the top and give the tin a little tap to even out the top.
Place in the fridge and leave to chill for a minimum of 3 hours.
Decorate with freeze dried raspberries and a sprinkling of cocoa or cacao powder.