• 40 g (1½ oz) dried porcini mushrooms
• 250 ml (9 fl oz/1 cup) boiling water
• 3 tablespoons olive oil
• 750 g (1 lb 10 oz) onions, finely sliced
• 1 teaspoon soft light brown sugar
• 2 tablespoons dry sherry
• 600 ml (21 fl oz) porcini mushroom stock
• sea salt flakes
• freshly ground black pepper
• 4 slices country-style bread
• 4 heaped tablespoons grated non-dairy cheese, plus extra to serve
• 1 squeeze lemon juice

In a small bowl, cover the porcini mushrooms with the boiling water. Set aside to soak for 30 minutes. Drain, squeeze out excess liquid and reserve the soaking liquor.

Meanwhile, in a heavy pan, heat the oil over a medium heat and add the onions. Stir to coat in the oil and add a splash of water. Reduce the heat to low, cover and gently cook for about 45 minutes. Take the lid off and stir occasionally during this time to ensure the onions are not sticking to the pan, adding a splash more water if needed. Increase the heat, stir in the sugar and cook for a few more minutes uncovered until starting to caramelise. Add the sherry, stock and reserved porcini soaking liquor and bring to the boil. Reduce the heat, season with salt and pepper and gently simmer for 10 minutes.

While the soup is simmering, toast the bread, top with the cheese and put under a hot grill (broiler) until the cheese is bubbling and melted. Add the squeeze of lemon juice to the soup and taste for seasoning. Put the cheesy toast in the bowls and ladle over the soup. Alternatively, serve the toast alongside.