1: Melt the butter in a large, heavy-based saucepan over a medium heat. Add the onion and potato and cook gently, stirring from time to time, until softened (but don’t let them take on any colour), around 10-15 minutes.
2: Sprinkle the flour evenly over the vegetables in the pan and cook, stirring, for 1-2 minutes, then stir in the chicken stock. Whack up the heat and bring to the boil, then reduce to a simmer and cook gently for about 10 minutes until the soup has thickened. Pour in the ale and heat gently for a further few minutes.
3: Remove from the heat, let cool slightly and then transfer the mixture to a blender or food processor. Add the cream and whiz until nice and smooth.
4: Pass the soup through a fine sieve into a clean saucepan and season with pepper and a little salt – do not add too much at this stage as the cheese will introduce extra saltiness later.
5: To make the dressing, whisk together the olive oil, malt extract and cider vinegar in a small bowl until emulsified.
6: Warm the soup gently over a low heat and stir in the grated cheddar, allowing it to melt. Taste and adjust the seasoning if necessary.
7: Ladle the soup into warmed bowls and trickle a little dressing on top of each one. Sprinkle on the diced apple and chives and serve immediately.