Heat the oven to 200C/400F/Gas Mark 6 and grease a baking sheet with a little oil or line it with baking paper.
Tear the kale leaves into bite sized pieces and boil or steam them for a few minutes until tender. Refresh by running under cold water to cool, then drain, squeeze out any excess moisture and puree to a paste with a hand blender. Note: Kale can be fibrous, so if necessary add a little of the buttermilk to aid pureeing.
Sift the flour, bicarbonate of soda, herbs, sea salt and sugar into a large mixing bowl, adding any sifted out herbs or salt back to the bowl, and make a well in the middle.
Stir the pureed kale into the buttermilk, then add it to the well in the dry mixture, and stir with a wooden spoon until it forms a sticky dough.
With floured hands, pat the dough into a ball and flatten slightly, then place on the baking sheet.
Cut a deep cross across the top with a knife and sprinkle it with a little flour.
Bake for 30 minutes or until the top is golden and tapping the bottom of the soda bread makes a hollow sound. Allow to cool on a wire rack.
Make it vegan: use non-dairy milk with 1 teaspoon vinegar or lemon juice instead of buttermilk