1. For sauce: Combine the mustard, anchovy paste, butter and lemon zest in a
non-reactive small saucepan. Add 2 tablespoons of the lemon juice and put the
saucepan over very low heat. Cook stirring constantly, until you have a thick cream -
the butter should not melt enough to separate. Take pan off heat and add capers.
2. For fillets: Rinse the turbot fillets, pat dry and salt lightly. Pour the oil into a 9 1/2
inch nonstick skillet and place over medium heat. When the oil is hot, lay the fillets in
the pan with what would have been the skin side down. Cover the pan with a
perforated lid and cook over low heat for 8 minutes.
3. To serve: Transfer the fillets to 2 plates and coat them with caper sauce - it will melt
slowly on contact with the hot fish - and serve at once.