To make the tart base, blend biscuits in a food processor until finely crumbed, add melted butter and pulse until combined. Press the mixture into the bottom and sides of a greased 23cm tart tin. Using a flat-bottomed glass or cup can help to press the mixture firmly in to the base and sides of the tin. Refrigerate for at least 30 minutes to firm up before adding the filling.

To make the filling, add dark and milk chocolate dotties to a medium bowl or jug. In a small saucepan over medium heat, bring the cream and butter to almost boiling point. Remove from the heat and immediately pour mixture over the chocolate so that it is submerged. Let stand for a few minutes to allow the chocolate to melt, then stir mixture until smooth. Pour mixture over chilled tart base and quickly but gently smooth out. Pop any large bubbles that rise to the surface using a toothpick or the point of a sharp knife. Refrigerate for at least four hours until set.

Remove from refrigerator 10 minutes prior to serving. To serve, remove from tin and dust generously with cocoa powder. Slice with a warmed knife for a clean cut. Serve with double cream and berries if you wish.

To make the tart base, blend biscuits in a food processor until finely crumbed, add melted butter and pulse until combined. Press the mixture into the bottom and sides of a greased 23cm tart tin. Using a flat-bottomed glass or cup can help to press the mixture firmly in to the base and sides of the tin. Refrigerate for at least 30 minutes to firm up before adding the filling.

To make the filling, add dark and milk chocolate dotties to a medium bowl or jug. In a small saucepan over medium heat, bring the cream and butter to almost boiling point. Remove from the heat and immediately pour mixture over the chocolate so that it is submerged. Let stand for a few minutes to allow the chocolate to melt, then stir mixture until smooth. Pour mixture over chilled tart base and quickly but gently smooth out. Pop any large bubbles that rise to the surface using a toothpick or the point of a sharp knife. Refrigerate for at least four hours until set.

Remove from refrigerator 10 minutes prior to serving. To serve, remove from tin and dust generously with cocoa powder. Slice with a warmed knife for a clean cut. Serve with double cream and berries if you wish.