braised fish with vermouth sauce
Escoffier's braised fish fillet with a vermouth and mushroom essence 
If there's one thing worth keeping in the pantry instead of a bottle of white wine, it's a good dry white vermouth. This braise from Escoffier pairs it with mushroom essence, a light fish fumet and a touch of cream, three elements that turn up again and again in his chapter on sole and other fish, used alone or together. Once you understand how they work as a trio, you can apply the same logic to almost any delicate white fish. Auguste Escoffier mentioned in his Guide Culinaire that John dory filets are an excellent replacement for sole if you cannot get it where you live.
SERVES 2
INGREDIENTS
For the Mushroom Essence
100 g (3.5 oz) small button mushrooms, quartered
15 g (1 tbsp) unsalted butter
5 ml (1 tsp) lemon juice
Salt and pepper to taste
For the Fish
15 g (1 tbsp) unsalted butter, for the dish
20 g (2 tbsp) finely diced shallot
2 (150 g / 5.3 oz total) sole fillets, or turbot, flounder, or orange roughy
Salt and pepper to taste
20 ml (2 tbsp) dry white vermouth (Noilly Prat or other french brand)
15 ml (1 tbsp) fish fumet or good-quality store bough fish stock
15 ml (1 tbsp) mushroom essence (from above)
30 ml (2 tbsp) heavy cream (optional)
15 g (1 tbsp) unsalted butter, cut into small cubes
7 g (1 tbsp) breadcrumbs
MISE EN PLACE
You will need a rectangular or oval ovenproof baking dish, large enough to lay the fillets flat without overlapping. Or two Individual dishes (if you do that you will have to split the liquids in 2 for each one)
Preheat the oven to 220°C (425°F).
Trim and clean the fish fillets and pat dry with paper towel.
METHOD
To make the mushroom essence, place the mushrooms in a small saucepan and pour in just enough water to barely cover them. Add the lemon juice, butter and a pinch each of salt and pepper, then bring to the boil and cook for 6 minutes. This is the classic technique for keeping the mushrooms pale while pulling their flavour into the cooking liquid, which becomes your mushroom essence. When cooked just leave the mushrooms in the pan in the cooking juices.
For the braise: Butter the baking dish generously and scatter the shallot over the base. Lay the fillets on top, skin side down, and season lightly, taking care not to oversalt as the fumet will already carry some seasoning. Pour in the vermouth, fumet and the mushroom essence, aiming for the liquid to reach no more than halfway up the fillets. Scoop out the mushrooms out of the cooking juice and scatter over the fish, then spoon over the cream (if using). Dot with the butter cubes and finish with a light sprinkle of breadcrumbs for texture.
Transfer to the oven and cook for 10 to 12 minutes, or until the fish flakes easily and the sauce has reduced slightly around it. Serve straight from the dish with crusty bread to mop up the sauce.
Tip
Vermouth brings a much more subtle flavour compared to white wine and it’s worth having bottle in your spirit cabinet. That said, if you don’t have it, of course white wine also works. If you're cooking more fillets, increase the liquid proportionally, but resist the urge to drown the fish. Too much liquid and the sauce turns soupy rather than reduced (however the flavours won’t suffer).