Wash and dry the duck fillet. Cut in the middle into two parts, cut the skin obliquely to the meat.
Prepare the marinade. Mix soy sauce with mustard, honey and lemon juice.
Put in the marinade the duck breast. Salt and pepper. Leave to marinate for 1.5-2 hours. Then to get the fillets from the marinade and fry on a dry pan for a few minutes on both sides. First fry the side with the skin.
Put the duck in a baking dish and send it to the oven, preheated to 200* for 10 minutes in convection mode.
Put the duck fillet on a plate.
Cover tightly deep plate for about 10 minutes. During this time it will juice.
The remains of the marinade pour into a saucepan, add 1 tablespoon of lemon juice (if necessary), 15g of butter and evaporate over medium heat until the sauce thickens.
Sauce strain, cool.
Defrost the beans. Boil in salted water for 5-7 minutes.
Throw in a colander, cool.
Fillet cut obliquely, put on a dish with arugula, frieze salad and boiled string beans.
Pour the sauce over the duck. Serve with olive oil (for greens).