1. Wash the cavolo nero leaves and leave then wet. You can cut out the centre ribs if you like, but I rarely bother.
  2. Stack a half dozen or so of the leaves, roll them up lengthwise, and slice the roll into thin strips (aka chiffonade). Do this to the entire bunch, then add it to the onion.
  3. Pour in about a half cup of water.
  4. Cook covered over low heat for at least 30 minutes (I think it’s even better if you cook it another 15 or so), stirring occasionally to prevent scorching. Add a little more water if the pan starts to dry out.
  5. Drizzle with a bit of your very best extra virgin olive oil at the table.

Slow cooked beans go really well with this.