For the salmon on a bed of vegetables, wash the lemon, grate the zest and squeeze out the juice. Wash the salmon fillets, dab dry and marinate with the lemon juice, lemon zest and a little salt for about ½ hour.
Cut the leeks into thin rings and rinse thoroughly. Peel the sweet potatoes and grate coarsely.
Sauté leek rings in olive oil for 2-3 minutes, add sweet potatoes and fry briefly, then reduce heat, season and cook in closed pot for about 8 minutes. Preheat oven to 90 °C convection oven.
Prepare a roasting tube according to package instructions, fill in leek-sweet potato vegetables, place the two marinated salmon fillets on top and close the tube tightly with as much air as possible.
Place the packet in the tube and let it cook for about 30 minutes. In the meantime, peel the potatoes, cut into cubes and boil in the soup for 10 minutes until soft.
Mash with a potato masher and season if necessary. Serve the finished salmon with the vegetable bed and the mashed potatoes.