Lentil Mushroom Soup with Gremolata

steps

1. Add dried porcini to boiling water and steep for 10 minutes. Drain, reserving soaking liquid, and finely chop mushrooms.
2. Heat 1 tablespoon olive oil in a large dutch oven over medium-high heat until shimmering. Add carrot, onion, celery, and 1 teaspoon salt and cook, stirring occasionally, until softened, about 3 to 4 minutes. Add remaining 1 tablespoon olive oil, sliced cremini mushrooms, 1½ teaspoons garlic, ½ teaspoon red chile flake, thyme, and 1 teaspoon salt and cook, stirring occasionally, until mushrooms have softened and released their liquid, 6 to 8 minutes.
3. Add broth and chopped porcinis and their soaking liquid to the pot, cover, and bring to a boil over high heat. Add lentils and 1½ teaspoons salt and return to a boil, then reduce to a simmer and cook, covered, until lentils are tender, 45 minutes.
4. Transfer 2 cups of soup to a blender, secure lid, and remove center piece to allow steam to escape. Blend until smooth, 1 minute, then return to dutch oven and stir to combine. Season with salt.
5. While soup simmers, add remaining grated garlic, lemon zest, parsley, and remaining red chile flake to a small bowl and stir to combine. Serve soup in individual bowls and top with gremolata.