Haddock with leek and potato sauce

Ingrediënten

• 50g peeled and finely sliced potato (approx. 1 small potato)
• 10g unsalted butter
• 35g peeled and finely sliced onion (approx. ½ onion)
• 160g cleaned and very finely sliced leek (approx. 3 leeks)
• 200g fish stock (p.42), warmed
• 10g whipping cream
• 10g whole milk
• Salt and white pepper
• Groundnut oil
• 2 haddock fillets, weighing 150–200g each, skinned
• Chives and tarragon, to garnish