The biggest mistake made with mussels is throwing out the juice they release when they're cooking. This mussel liquor is intensely flavoured and redolent of the sea - sweet and salty. Here it becomes the base of the velouté. You'll need to begin this a day ahead to soak the saffron (see tip below).
- 2½ tbsp extra-virgin olive oil
- 2 kg black mussels, scrubbed
- 200 ml dry apple cider
- 120 gm butter, coarsely chopped
- 2 leeks, washed thoroughly, halved lengthways and thinly sliced
- 80 gm plain flour
- 1 tsp saffron, soaked overnight in 2 tbsp hot water
- ½ cup (loosely packed) flat-leaf parsley leaves, to serve
- 1Heat olive oil in a large saucepan over high heat, add mussels and cider, cover with a lid and cook, shaking pan occasionally, until mussels open (1-2 minutes). Remove from heat, strain juices and reserve mussels and juices separately.
- 2Heat butter in a large saucepan over low-medium heat, add leek and stir occasionally until tender (7-8 minutes). Add flour and stir to combine (1-2 minutes). When it starts to bubble, stir in saffron and soaking water, then add 750ml of reserved mussel juice (top up with water if necessary), increase heat to medium and stir continuously until sauce thickens (1-2 minutes). Let it bubble for a minute, then stir in mussels and serve hot scattered with parsley.
Hot tip Soaking your saffron overnight extracts the full benefit - in flavour and colour. Consider buying locally grown saffron, which is usually much fresher than imported examples.