Here's how:

1 Put flour, cocoa and sugar in a food processor and process for 30 seconds. Add butter and process until mixture resembles fine breadcrumbs. Add egg and process until dough just comes together. Turn onto a board and knead gently until dough comes together. Form into a 2cm-thick round. Wrap in baking paper and refrigerate for 20 minutes or till firm.

2 Preheat oven to 180ºC. Lightly grease 2 x 12-mould mini muffin tins. Roll pastry out between 2 sheets of baking paper to 5mm thick. Using a 6.5cm round cutter, cut 24 rounds of pastry. Put into prepared tins. Bake for 15 minutes or until firm to the touch. Allow to cool.

3 Stir condensed milk, golden syrup, brown sugar and extra butter in a non-stick pan over a medium-low heat until mixture comes to the boil. Reduce heat to low and cook, stirring, for 10 minutes or until thick. Cool. Spoon caramel into pastry cases. Return to oven for 5 minutes. Cool, then spread tarts with ganache.

4 To make ganache, heat cream in a saucepan until almost boiling. Remove from heat, add chocolate, and stir until melted and smooth. Cool ganache at room temperature until thick enough to spread.