Three Mushroom Soup with Lemongrass

2 tablespoons olive oil
2 medium yellow onions, halved and thinly sliced
8 ounces cremini or white button mushrooms, cleaned and thinly sliced
8 ounces shiitake mushrooms, stems removed and discarded, caps cleaned and thinly sliced
1â„2 cup dry sherry or dry vermouth
1 lemongrass stalk, cut into 2-inch sections, each bruised with a mallet or the bottom of a heavy pot
6 cups (11â„2 quarts) vegetable broth
1 small bunch enoki mushrooms, cleaned and separated
1â„2 teaspoon salt
1â„4 teaspoon freshly ground black pepper

Heat a large saucepan over medium heat. Swirl in the olive oil, then add the onions and cook, stirring often, until soft, about 4 minutes.
Add the cremini and shiitake; cook, stirring often, until they brown slightly and begin to give off their liquid, about 3 minutes.
Add the sherry or vermouth and the lemongrass. Raise the heat to medium-high and boil until the liquid in the pan has reduced by half, about 3 minutes.
Pour in the broth; bring to a simmer over medium- high heat. Cover, reduce the heat, and sim- mer slowly until the mushrooms are quite tender, about 8 minutes.
Stir in the enoki, salt, and pepper. Cover and set aside off the heat for 5 minutes. Remove and discard the lemongrass pieces before serving.

Slice 6 ounces pencil-thin asparagus spears into 1-inch segments and add them with the enoki.
Add 8 ounces small broccoli fl orets (or large fl orets cut into slices) with the enoki.
Omit the lemongrass; add 1 teaspoon fi nely grated lemon zest, 3 parsley sprigs, and 2 bay leaves in its place; remove the parsley and bay leaves before serving.
Omit the lemongrass; add 2 tablespoons chopped lemon balm in its place.
For a thicker soup, whisk 3 tablespoons tomato paste into the sauce before adding the broth.