Make the middles first. Heat the Dulce de Leche in a pan for 1 min until warmed and runny, then stir
in the chopped dark chocolate and leave to melt. Stir until smooth. Cover a dinner plate with cling film, oil the cling film well, then tip the mix onto
it. Cool, then freeze for 2 hrs or until very firm.
Put the milk chocolate into a bowl. Bring the cream to the boil in another pan, then pour it over the chocolate. Leave for 2 mins, then add the
vanilla and stir until smooth.
Cool, then chill until set.
Peel the caramel from the cling film, then snip into thumbnail-size pieces; wet kitchen scissors work best.
Spread cocoa powder over a large baking tray. Take a heaped tsp of the truffle mix then, with cocoa-dusted hands, poke in a caramel chunk. Squash the mix around the caramel
to seal, then roll into a ball. Put onto the tray, then shake to coat in the cocoa. Repeat with the rest of the mix, then freeze, or chill if making less than
3 days ahead.