1 1/2 kg fresh mussels
30 g unsalted butter
15 ml olive oil
2 shallots, finely chopped (about 60 g)
3 cloves garlic, finely sliced
150 ml dry white wine
100 ml fish stock or water
50 ml double cream
10 g fresh flat-leaf parsley, finely chopped
10 g fresh dill, roughly chopped (plus extra for garnish)
1 bay leaf
2 g fine sea salt, or to taste
2 g freshly ground black pepper, or to taste
1 lemon, cut into wedges, for serving
Crusty bread, to serve