Mexican Chile and Mushroom Soup

Preparation

1. Step 1

   Heat a dry 12-inch heavy skillet over moderate heat until hot, 3 to 5 minutes. Lightly smash garlic in skins with side of a large knife, then add to skillet along with onion slice and cook, turning over once or twice with tongs, until onion is well browned and garlic is slightly softened, about 8 minutes.

   Step 2

   Meanwhile, discard stem, seeds, and veins from chile and tear chile into 4 pieces. Add chile to onion and garlic in skillet and toast, pressing flat with tongs and turning over occasionally, until chile turns a brighter red, about 1 minute.

   Step 3

   Discard garlic skins and coarsely chop onion, then purée garlic, onion, and chile in a blender with water, salt, and oregano until smooth.

   Step 4

   Heat oil in skillet over high heat until hot but not smoking, then sauté mushrooms, stirring occasionally, until golden and any liquid is evaporated, about 6 minutes. Reduce heat to moderate, then add tomato paste and cook, stirring, 1 minute. Add purée and cook, stirring, 3 minutes. Stir in broth and simmer 5 minutes.