Mushroom Strudel

Ingredients

• 0.5 ounce the following: parmesan rind) dried ()
• 0.3 cup wine dry white
• 2 tablespoons flat parsley finely chopped
• 2 tablespoons butter unsalted melted
• 12 inch sheets dough frozen thawed (17-by 12-inch)
• 0.3 cup shallots finely chopped ( 2 large)
• 2 tablespoons butter unsalted
• 0.5 cup water 
• 0.5 pound mushrooms fresh white trimmed halved lengthwise

Equipment

• food processor
• bowl
• frying pan
• baking sheet
• paper towels
• oven
• sieve
• plastic wrap
• serrated knife

Directions

1. Soak porcini in boiling-hot water in a small bowl until softened, about 10 minutes. Lift out porcini and squeeze excess liquid back into bowl. Rinse porcini well to remove any grit. Strain soaking liquid through a sieve lined with a dampened paper towel into another bowl and reserve.
2. Pulse porcini and white mushrooms in a food processor until finely chopped (but not minced).
3. Cook shallots in butter in a large heavy skillet over medium heat, stirring, until beginning to soften, about 1 minute.
4. Add mushrooms, reserved soaking liquid, wine, 1/2 teaspoon salt, and 1/4 teaspoon pepper and cook, stirring occasionally, until liquid has evaporated, about 8 minutes. Stir in parsley, then spread filling on a plate and chill, uncovered, until cold, about 10 minutes.
5. Preheat oven to 425°F with rack in middle.
6. While filling chills, put stack of phyllo sheets on a work surface and cut in half crosswise, then stack halves and cover with plastic wrap.
7. Remove 1 phyllo sheet from stack (keep remaining sheets covered) and arrange with a long side nearest you, then lightly brush with some duck fat. Top with another phyllo sheet and brush with fat.
8. Spread about one fourth of mushroom filling in a narrow strip along edge nearest you to within 1/4 inch of each end, then roll up phyllo tightly around filling, leaving ends open.
9. Transfer roll, seam side down, to a baking sheet and make 3 more rolls in same manner, transferring to baking sheet.
10. Bake until golden brown, 12 to 14 minutes. Cool slightly on baking sheet on a rack, then brush length of each roll with a very thin line of truffle oil (if using) with tip of a cotton swab. Gently cut each roll crosswise into 8 pieces with serrated knife.
11. Serve strudel warm or at room temperature.
12. •Mushroom filling can be made 2 days ahead and chilled (covered once cool).•Strudels can be assembled (but not baked) 1 day ahead and chilled, or 2 weeks ahead and frozen, wrapped well in plastic wrap.
13. Bake (do not thaw first) in a preheated 350°F oven 20 minutes.