Add the mustard mixture and simmer over medium heat for 5 minutes.
Brush top of salmon with remaining olive oil and then with mustard mixture.
Season the quail with salt and pepper and coat with the mustard mixture.
Stir in the grated orange zest and the remaining mustard mixture.
Toss thighs in bowl with mustard mixture, slathering them, then place over leeks.
Place steaks in dish, and smear mustard mixture on both sides of each steak.
Place monkfish in a glass or ceramic dish and pour six tablespoons of mustard mixture over fish, turning each piece to coat both sides.
Stir in the reserved vinegar and mustard mixture.
Spread just a teaspoon or so of the mustard mixture on the underside of the chicken, and broil about 5 minutes.
Then with a pastry brush, brush the chicken on both sides with the mustard mixture.