Have six 4- to 6-oz. ramekins or teacups ready for pouring.
Heat the heavy cream in a small saucepan or microwave until just boiling. Remove from the heat and whisk in the cocoa powder until smooth. Add the chocolate, butter, sugar, vanilla extract, and salt, and whisk until the chocolate and butter are melted and the mixture is smooth.
Pour the mixture into the ramekins or cups. Depending on the size of the ramekins, they'll be filled about two-thirds to three-quarters of the way.
Cover with plastic (not touching the surface of the puddings) and refrigerate until chilled and thickened, at least 6 hours or up to 3 days.
Serve with a dollop of sweetened whipped cream and a few chocolate shavings, if you like. Ripe raspberries are a beautiful adornment and also taste delicious with the chocolate.
Other options: change out vanilla extract for orange, raspberry, or hazelnut liqueur or flavoring. Serve right after making for chocolate soup. Change out the 70% chocolate for sweeter semi-sweet or even milk chocolate. Take note; if you use anything less than 70%, the pudding will remain pourable as it won't set completely. Still fabulous, though!