I had mussels as well last night (no, I'm not Mrs D posting in a fit of rebellion), a mussel and prawn gratin. It was a recipe from t'internet that a Portuguese man had randomly posted. The English was a bit pigeon so not sure if I did it right.
Fry some chopped shallots and garlic in olive oil add 2 cups prawns and equal amount of mussels and saute for a few seconds longer. Add splash of dry white wine, salt and pepper. Drain juices and save for later. Add couple of fistfuls of spinach, cover pan and let sweat for a couple of minutes until spinach wilted. Butter an oven dish liberally and empty mixture into the bottom.
Into a heavy saucepan (I used a small cast iron Balti pan, the curved surface heats the sauce from all sides gently and it thickens great) melt 2 tablespoons of butter, stir in a large tablespoon of plain flour to make a thickish roux. Gradually add half a litre of hot milk. When it starts to thicken add the discarded juices, salt, pepper and a snooker-ball sized amount of grated cheddar. Once brought to the boil and thickened, remove from heat and add 1 egg and 2 further egg yolks, beaten so they're just mixed. Stir in thoroughly. Pour over mussel concoction, let cool for a minute or so, then cover surface with lots more grated cheddar. Bake in the oven for about 20 minutes until golden brown on top. When removed from the oven let it cool to set slightly for a few minutes.
It tasted sublime, like a savoury mousse-like souffle-type-thing that didn't overpower the shellfish, really melted in the mouth, but I think I went a bit overboard with the spinach 'cos it was a bit sloppier than the picture. It tasted even better when we polished off the rest today.
