Butter Bean Winter Greens Soup with Celery Gremolata

1. Heat the oil in a large saucepan over a medium heat and add the mirepoix ingredients: onion, celery and carrot and season generously with a pinch of salt. Cook, stirring often for 8 minutes, until the mirepoix mixture is completely tender.
2. Stir in the garlic and fennel seeds and continue to cook until fragrant. Add the tomato puree and cook for a couple of minutes more until the colour deepens from traffic light to rusty red. Tip in the tomatoes and fill the tin with water before pouring into the pan. Drain the butter beans and add these too, along with a generous pinch of salt and pepper. Bring the pan to the boil, then reduce to a simmer and cover with a lid to cook for 20 minutes.
3. Add the greens after this time, along with the vinegar and cover with a lid again for a final 5 minutes.  Taste and adjust the seasoning and keep warm before serving.
4. To make the gremolata, pulse all of the ingredients together in a food processor to very finely chop, or very finely chop by hand using a chopping board. Transfer to a small bowl to serve at the table.
5. Ladle the soup into warm bowls to serve, with the gremolata, a generous drizzle of olive oil and parmesan at the table for everyone to help themselves to.

The soup will keep covered in the fridge for up to 5 days.

For the soup 

• 3 tablespoons extra virgin olive oil, plus extra for drizzling
• 2 onions, finely chopped
• 2 sticks celery, finely chopped
• 2 carrots, peeled and finely chopped
• 4 garlic cloves, finely chopped
• 1 tsp fennel seeds
• 2 tbsp tomato puree
• 1 x 400g tin chopped tomatoes
• 1 x 400g tin butter beans, drained and rinsed
• 100g kale or chard, leaves roughly torn and stalks discarded
• 1 tbsp red wine vinegar
• Salt & pepper

For the celery gremolata 

• 1 small stick celery, roughly chopped
• ½ small bunch parsley
• 1 garlic clove, roughly chopped
• Zest of 1 unwaxed lemon

To serve

• 50g parmesan, finely grated