Zucchini Lasagna

INGREDIENTS

• Olive oil for cooking
• 4 lb. zucchini, cut lengthwise into 1/4-inch-thick
• slices
• Salt and freshly ground pepper, to taste
• 4 cups ricotta cheese
• 1 cup grated Parmigiano-Reggiano cheese
• 2 Tbs. chopped fresh tarragon
• 1/3 cup unsalted butter
• 1/3 cup all-purpose flour
• 5 cups milk, warmed
• Freshly grated nutmeg, to taste
• 1 1/2 lb. fresh pasta, cut into lasagna noodles, cooked until just tender (see related recipe at left)
• 4 lb. tomatoes, peeled, seeded and coarsely chopped
• 1 lb. mozzarella cheese, shredded