4 ounces dried mushrooms, such as porcini or chanterelle
4 cups boiling water
2 sprigs fresh rosemary
2 sprigs fresh thyme, plus 2 teaspoons finely chopped
7 tablespoons unsalted butter
5 tablespoons all-purpose flour
1 1/2 cups heavy cream
1 onion, diced
1 pound button mushrooms, stems removed, quartered
1 pound shiitake mushrooms, stems removed, sliced
2 1/2 teaspoons coarse salt
1/2 teaspoon freshly ground pepper
1 pound linguine
Unsalted butter, for pan
1/2 cup grated pecorino Romano cheese