Finely chop the liquorice and put in a small pan with about 5cm water. Boil for 30 mins, topping up with water to keep the liquorice covered at all times, mashing and stirring occasionally, until nearly all the lumps of liquorice have disappeared and you’re left with black, syrupy water. Sieve into a new pan, add the butter, and gently bubble until you have a consistency between clear honey and gravy.
Boil a big saucepan of water. Add the carrots and cook for a couple of mins until just tender. Drain well, then tip back into their pan and add the hot liquorice syrup. Toss to coat, season, and tip into a dish to serve.