One 10-ounce package fresh white mushrooms, chopped fine (preferably in a food processor)
1 tablespoon Worcestershire sauce
1 tablespoon medium-dry Sherry (if desired)
1 garlic clove, minced and mashed to a paste with 1/4 teaspoon salt
1/4 cup pine nuts
1/4 cup freshly grated Parmesan cheese
1/2 cup packed fresh parsley leaves, washed well and spun dry
1 pound Penne rigate (ridged Penne) or other tubular pasta
How to make it
In a 6-quart kettle bring 5 quarts salted water to a boil for pasta.
Prepare the pesto:
In a 10 to 12-inch non-stick skillet heat 1 tablespoon olive oil over moderately high heat until hot but not smoking and saute mushrooms with Worcestershire sauce, Sherry, and salt and pepper to taste, stirring, until liquid mushrooms give off is evaporated and mushrooms begin to brown, about 10 minutes.
In a food processor puree mushroom mixture with garlic, pine nuts, Parmesan cheese, and remaining 3 tablespoons olive oil.
Add parsley and blend until parsley is chopped fine. Pesto keeps, surface covered with plastic wrap, chilled, 1 week.
Prepare the pasta:
Cook pasta in boiling water until 'al dente'.
Reserve 1 cup cooking water and drain pasta.
In a large bowl whisk together pesto and 2/3 cup reserved hot cooking water.
Add pasta and toss well, thinning pesto, if necessary, with remaining reserved cooking water. Serves 6.