Mix together in a bowl the soy sauce, mirin sauce and ginger.
Zest the lemon with a fine grater. Squeeze 2 tea spoons of juice.
Cut the Atlantic salmon fillet into large pieces.
Put the fish into a deep glass container and pour the marinade into it.
Put the fish into a baking form, pour some marinade, put on the top smashed garlic and onion.
Thoroughly cover the fish with foil and put into the oven to bake at approximately 180°C for about 20 minutes.
Dredge cut green onion and sesame onto the cooked Atlantic salmon.