Jerusalem Artichoke Soup and Chips

For the Jerusalem artichoke soup

• Melt the butter with the olive oil in a large saucepan set over a medium heat.
• Add the onion, celery, garlic, and a pinch of salt, and sweat for 6-7 minutes until softened.
•  Stir in the dried thyme and marjoram, and then the diced Jerusalem artichoke.
• Cover with the stock, bring to the boil, then cover and cook at a steady, gentle simmer for 35-40 minutes until the artichoke is very tender to the tip of a knife.
• Purée the soup with an immersion blender or in a food processor, working in batches if necessary.
• Return the soup to a gentle simmer over a medium-low heat and stir in the cream.
• Adjust the seasoning to taste before covering and setting aside.

For the Jerusalem artichoke crisps

• Thinly cut the artichokes on a mandoline set to a very thin setting.
• Rinse the slices in a bowl of cold water before draining.
• Rinse and drain three times in total before drying the artichoke slices with kitchen paper.
• Heat the oil in a heavy-based saucepan to 180°C | 355F, using a thermometer to accurately gauge the temperature.
• Deep-fry the artichoke slices in batches, turning occasionally, until lightly golden, about 3-4 minutes.
• Remove from the oven and drain on kitchen paper.
• Repeat for the remaining batches.

To serve

• Reheat the Jerusalem artichoke soup over a gentle heat.
• Ladle into warm bowls and top with the artichoke crisps and some thyme before serving.