FOR THE AIOLI
6 garlic cloves
2 egg yolks
juice ½ lemon
1 tsp Dijon mustard
200ml oil (a mix of sunflower and olive oil is best; choose a ratio to your taste)
FOR THE MUSSELS
2-3 tbsp olive oil
1 onion, thinly sliced
2 bay leaves
250ml dry white wine
1 leek, white part only, finely sliced
1 small fennel bulb, finely sliced
1 carrot, trimmed and thinly sliced
2 pinches of saffron
day-old crusty bread, to serve
For the aïoli, grate the garlic into a food processor and add the egg yolks, lemon juice, mustard and seasoning. Blend until smooth. With the machine running, trickle in the oils just until you have a smooth, thickish paste. Set aside in the fridge.
For the mussel stew, clean and debeard the mussels. Discard any that are open and do not close when given a sharp tap. Heat a large pan with a lid over a high heat. Add half the oil and half the onion. Fry gently for 5 mins or until soft but not coloured. Add the bay leaves and a splash of wine. Increase the heat and, when it begins to bubble, add the mussels and 200ml water.
Cover pan with a lid and cook for 4-5 mins or until the mussels have opened. Tip into a colander set over a bowl to catch the liquor. Check through the mussels, discard any that remain shut and, when cool enough to handle, pick the meat from the shells. Strain the cooking liquid through a sieve.
Fry the remaining onion in olive oil for a few mins to soften. Add the leek, fennel and carrot, and cook for 5 mins. Add the remaining wine, the reserved cooking liquid and a little more water, if necessary. Heat gently, stir in the saffron and season, then simmer for 10 mins. Whisk in 1 tbsp of the aïoli to thicken, then stir in the mussels and allow them to heat through.
To serve, put a slice of bread in the base of each warmed serving bowl and pour in the stew. Serve at once with a bowl of aïoli on the side and more crusty bread for dipping.