This is a deeply comforting, nourishing green soup, perfect for when the weather starts getting chillier and your body needs a boost of iron. The dish relies on a confident hand with the seasoning, because the potato and greens need plenty to allow their flavours to shine, but shine they will. And never was there such a good use for stale bread as in the making of parmesan croutons, the umami flavour bombs that bring all these notes together.
There are plenty of croutons here, so pile them high in your soup bowl and let them soak up all that green goodness.
Prep 15 min
Cook 45 min
4 tbsp olive oil
1 large leek, halved, washed and sliced
6 garlic cloves, peeled and sliced
1 bay leaf
Salt and pepper
400g floury potatoes, peeled and roughly chopped into chunks
1¼ litres vegetable or chicken stock
300g cavolo nero, or other kale, stems removed, leaves roughly chopped
Creme fraiche, to serve
For the croutons
200g stale sourdough, crusts removed, the rest ripped into small pieces
3 tbsp olive oil
3 tbsp grated parmesan, plus extra, to serve
Heat the oil in a large pan, add the leek, garlic, bay leaf and a pinch of salt, and cook gently for 10-15 minutes, until soft and sweet. Add the potatoes and 500ml stock, and boil for 10 minutes. Add the cavolo nero, pour in the remaining 750ml stock, cover and simmer for about 15 minutes, until the potatoes are soft and the cavolo nero is very tender. Add the spinach just at the end, and give the leaves a minute or two to wilt.
Meanwhile, heat the oven to 200C (180C fan)/390F/gas 6. Toss the bread in the oil, and parmesan, season, then spread out on a lined tray. Bake for 10-15 minutes, until golden and smelling irresistible.
Blitz the soup with a hand blender until smooth (or do so in a food processor). Add some healthy grindings of nutmeg, taste and adjust the seasoning.
Serve with a big pile of croutons sprinkled over, a small dollop of creme fraiche and a little extra parmesan, if you want.
Although I love the simplicity of the vegetables in this soup, it is also delicious with the addition of sauteed diced pancetta at the beginning. You can garnish the soup with extra-virgin olive oil instead of creme fraiche, if you prefer less dairy.