In this part of the recipe there are two distillations. First is a distillation of the outer leaves of the radicchio and the second distillation is of the radicchio hearts in the pig jowl liquor.
For the first distillation, remove all the outer leaves from the radicchio, so you are only left with the very small hearts. Set aside the hearts.
Set up a twin-gear juicer (wheatgrass style) and put the vitamin C powder in the juice-collection jug to help to stop the juice turning brown. Juice the leaves.
Place the juice into a 3 litre (105 fl oz) capacity distillation flask and add the sugar. Place in a rotary evaporator*, set the water bath temperature to 30°C (86°F) and the cooling temperature to −25°C (−13°F), set the rotation speed to 55 RPM and distil at full vacuum for 15 minutes (depending on the strength of the vacuum) or until the juice has reduced to a deep brown syrup. Watch out that the juice doesn’t boil over at the beginning of the distillation. Invert the flask over a container to drain for 10 minutes. Store the radicchio leaf distillation in an airtight container until needed.
For the second distillation, warm the pig jowl cooking liquor in a small saucepan and skim off all the fat.
Place the radicchio hearts, water, pig jowl cooking liquor and verjus in a 6 litre (210 fl oz) capacity distillation flask, place in a rotary evaporator*, set the water bath temperature to 40°C (104°F) and the cooling temperature to −25°C (−13°F), set the rotation speed to 30 RPM and distil at full vacuum for 5–10 minutes or until the hearts are glazed. Turn off the vacuum and remove the flask from the machine. Tip the radicchio hearts and glaze into a bowl, add the lemon juice and check the seasoning — the pig jowl liquor will be quite salty so it may not need more salt.
When ready to serve, cut each heart in half and sear, cut side down, in a hot non-stick frying pan for 10 seconds.