Preheat oven to 375 degree F. Prepare Mushroom-Onion Filling. Lightly brush a sheet of phyllo with some of the melted butter. Sprinkle 1 tablespoon fine dry bread crumbs over the phyllo sheet. Top with another sheet and brush with more melted butter. Sprinkle with 1 tablespoon more fine dry bread crumbs. (Keep remaining phyllo covered with plastic wrap to prevent it from drying.) Using a sharp knife cut the phyllo stack in half lengthwise and then in half crosswise to make four equal-size rectangles.

Spread about 1 rounded teaspoon of the mushroom filling in a 3/4-inch-wide strip along a long side of a phyllo rectangle; spread filling to within 1 inch of short ends of rectangle. Starting at the filled side, tightly roll the phyllo dough into a thin log. Brush seam with butter. Place log, seamside down, on a baking sheet; brush with butter and lightly sprinkle with pepper.

Bake in preheated oven for 12 to 15 minutes or until logs are golden brown. Cool on wire racks. Repeat with remaining phyllo, butter, bread crumbs, filling, and pepper. Place baked logs in covered containers and store at room temperature for up to 8 hours. Makes 24 logs.

In a large skillet, heat 2 tablespoons cooking oil until hot. Cook 4 cups finely chopped crimini and/or shiitake mushrooms; 2 large onions, finely chopped; and 2 cloves garlic, minced, over medium-high heat for 5 to 7 minutes or until mushrooms are tender and liquid has evaporated, stirring occasionally. Remove mixture and set aside to cool completely. Makes about 1-3/4 cups.

Prepare the recipe three times.