Ensure the mould is thoroughly clean and dry, paying particular attention to the ‘corners’ and edges of the mould’s design.
Prepare to temper the chocolate. Have a large baking tray, tea towel or square of kitchen roll, a ladle or spoon, and sharp knife to hand.
Begin to temper the chocolate. Break the 350g chocolate into a heatproof glass bowl. Build a bain marie by suspending the bowl over a pan containing some water, ensuring the water doesn’t touch the base of the bowl. Place the bain marie on the hob over a low – moderate heat. Allow the chocolate to start to melt. Stir the chocolate making a note of the temperature. Melt the milk chocolate to 46℃ / 115℉. Be careful not to take it any higher than this temperature as it could soon seize and become unworkable!
Cool the chocolate. Remove the glass bowl from the bain marie and sit it on the tea towel / kitchen roll. Stir the chocolate watching the temperature. You’re aiming for it to reduce to 26℃ / 80℉. This will take at least 10 minutes.
Reheat the chocolate. Return the bowl of chocolate to the bain marie. Continue to stir and monitor the temperature. You’re aiming for it to increase to 30℃ / 86℉. The chocolate is now tempered. Remove the bowl from the heat and sit it in the baking tray you have at your work station.
Fill the chocolate mould. Use a ladle or large spoon to pour chocolate into the prepared chocolate mould. Once completely full tap the chocolate mould on the work surface to try to dispell any air pockets in the chocolate. Tip the mould upside down over the bowl of melted chocolate to remove the excess chocolate. Give it a shake allowing the excess to drip out. Return the mould the right way round and return to the work surface. Run the sharp knife over the top of the mould to remove excess chocolate. This will neaten the edges of the chocolates and make it easier to remove them from the mould later. Check that all of the surfaces have been completely covered in chocolate. Touch it up with a little more as necessary. Remove the spoon and thermometer from the chocolate (it’ll set into the chocolate if you don’t!) and clean them ready for later.
Set aside to firm up. Set the chocolate mould aside for at least an hour whilst it firms up. Make the coffee ganache. Use a sharp knife to break up the 60g chocolate into small pieces. Place it into a bowl. Pour the cream into a small pan. Set over a low heat on the hob. Add the coffee granuals. Allow the coffee to dissolve as the cream heats up. Stir thoroughly. Once the cream is hot, though not boiling, pour it over the broken chocolate pieces. Stir thoroughly until it is smooth, shiny and completely combined. Set aside to cool a little.
Fill with the ganache (see notes c & d below). Once the chocolate in the mould has completely set and the ganache has cooled put half of the ganache into a piping bag (no nozzle required). Cut off the tip of the piping bag and pipe the filling into the chocolate shells. Aim to fill them no more than two-thirds full. Set aside for the ganache to firm up.
Cover with more chocolate. Reheat the remaining chocolate over the bain marie until it reaches 30℃ / 86℉. If the chocolate hasn’t completely melted at this point, or the temperature goes above 30℃ / 86℉ re-temper it as before. Spoon some of the melted chocolate over the ganache. Ensure that each chocolate mould is completely covered. Use the sharp knife to scrape away the excess.
Set aside. Set the chocolates aside to firm up.
Turn out. Once the chocolate has completely set turn the chocolates out. Wiggle the silicone mould to gently loosen them. Position the mould upside down over a clean tea towel or piece of kitchen roll. Gently push one of the silicone shapes to remove the chocolate. Repeat with the remaining chocolates.