Hederman's smoked mackerel toasts with Jerusalem artichoke soup– Frank Hederman

Ingredients

• 50g butter
• 1 tbsp sunflower oil
• 1 large onion, roughly chopped
• 600g Jerusalem artichokes peeled and chopped
• 2 large white potatoes such as maris piper peeled and chopped
• 1 garlic clove
• 800ml stock or water
• 30g soft butter
• 2 – 3 fillets of Hederman's Smoked Mackerel
• Nutmeg
• Chilli Flakes
• 1 small onion
• 2 gherkins or handful of capers chopped finely
• Salt
• pepper
• Butter
• Sliced sourdough or other rustic bread