This recipe uses Spanish chorizo. If all you can find is Mexican chorizo (which is fresh, not smoked and cured like the Spanish, and needs to be cooked more thoroughly), remove the meat from the casing, cook it in the oil in the skillet, stirring until it is just cooked through. Transfer the cooked chorizo to a medium bowl with a slotted spoon and proceed with the recipe as written.
Start to finish: 1 hour (45 minutes active)
Makes 30 stuffed mushrooms
2 tablespoons extra-virgin olive oil, plus extra
1/4 pound Spanish chorizo sausage
30 large (1 1/2 inches in diameter) cremini mushrooms
1/2 cup finely chopped yellow onion
1/4 cup dry sherry
1 slice firm white sandwich bread, cut into 1/4-inch cubes (about 1/2 cup)
1 ounce Manchego cheese, coarsely grated
1/4 cup fresh flat-leaf parsley leaves
Kosher salt and ground black pepper
DIRECTIONS: Heat the oven to 400 F. Use a bit of olive oil to lightly coat a rimmed baking sheet.
Remove the casing from the sausage and cut it into small dice. Trim and discard the dry ends of the mushroom stems. Remove the stems from the mushroom caps and finely chop them. Arrange the mushroom caps, open sides down, on the oiled pan and bake on the ovens middle shelf for 10 minutes.
Meanwhile, in a medium skillet over medium, cook the chorizo, stirring occasionally, until it begins to brown, about 3 minutes. Transfer the chorizo to a medium bowl with a slotted spoon.
Discard all but 2 tablespoons of fat from the skillet. Add the onion and cook until softened, about 5 minutes. Add the chopped mushroom stems and cook until the liquid the mushrooms release is almost all reduced. Add the sherry and simmer until almost all the liquid is reduced. Transfer the vegetable mixture to the bowl with the chorizo and set aside to cool slightly. Stir in the bread, cheese and parsley, then season with salt and pepper.
After the mushrooms have baked for 10 minutes, remove the pan from the oven. Carefully turn the mushroom caps over and divide the chorizo mixture among them, mounding it slightly. Bake the stuffed caps on the oven's middle shelf for about 15 minutes, or until the mushrooms are tender and the stuffing is golden brown. If the stuffing browns too quickly, cover the mushrooms loosely with foil.