Roasted Winter Vegetable Baklava

Name: Roasted Winter Vegetable Baklava
Ingredients: 1/2 cup walnuts (2 ounces), toasted; 1/4 cup fine dry plain bread crumbs; 1 pound Yukon Gold potatoes; 2 medium fennel bulbs, trimmed, reserving fronds, bulbs halved and sliced lengthwise 1/4 inch thick; 3/4 pound parsnips (3 medium), sliced diagonally 1/3 inch thick; 1/2 pound carrots (3 medium), sliced diagonally 1/3 inch thick; 1 large onion, halved and sliced; 3/4 cup olive oil, divided; 2/3 cup water; 1/3 cup chopped dill; 8 (17-by 12-inch) phyllo sheets, thawed if frozen; Equipment: a shallow 3-quart oval or rectangular baking dish