BBC Food - Recipes - Chestnut, roasted butternut squash and Bramley apple soup

Ingredients

• 1.5kg/3lb 5oz butternut squash , seeds removed, flesh cut into large wedges
• 5 tbsp olive oil
• 1 onion , chopped
• 1 garlic clove, finely chopped
• 2 potatoes, cut into cubes
• 1 Bramley apple , peeled, core removed, flesh chopped
• 2 litres/3½ pints hot chicken or vegetable stock
• 1 sprig fresh thyme
• 2 bay leaves
• 500g/1lb 2oz chestnuts , roasted and peeled, plus extra, sliced, to serve
• 400g/14oz ready-made chestnut purée
• salt and freshly ground black pepper
• truffle oil , for drizzling
• double cream , for drizzling (optional)