Heat the cream

• Pour the double cream into a saucepan.
• Lower the heat and bring it gently to a simmer.

Add the chocolate

• Break the dark chocolate and milk chocolate into small pieces.
• Add them to the hot cream.

Add butter, sugar and vanilla

• Add the unsalted butter, sugar and vanilla extract.
• Stir everything together well.

Stir until smooth

• Keep stirring over low heat; the chocolate may look separated at first, this is normal.
• Continue stirring until the butter melts and the ganache turns a dark, glossy colour.

Cool and set

• Switch off the heat and pour the ganache into a dish.
• Leave it at room temperature until completely cool.
• Then refrigerate until thick and firm.