- In a large pot over medium heat, soften the leek in the butter for 3 minutes without letting the leek brown. Add 1 lb (450 g) of the mushrooms. Cook for 4 minutes while stirring. Pour in the broth. Bring to a boil. Simmer for 20 minutes.
- In a blender, purée the soup until smooth. Season with salt and pepper. Return the soup to the pot. Add the remaining mushrooms and cook for 10 minutes. Adjust the seasoning.
- Meanwhile, in a large non-stick skillet over high heat, sear the lemon wedges in the oil on one side until nicely caramelized, about 3 minutes. Set aside on a plate.
- In the same skillet, sear the salmon pieces for 2 to 3 minutes on each side. Add more oil as needed. Remove the skillet from the heat. Leave the salmon pieces in the skillet until just pink at the centre. Drain on paper towels.
- Place the salmon pieces at the centre of four shallow bowls. Using a ladle, pour the soup around the salmon. Garnish with the dill and caramelized lemon wedges.
Choose salmon from the thickest part of the fillet.