Pasta and Lamb Casserole (Pastitsio)

Ingredients

• 1.8 cups sandwich bread fresh white firm (from 4 slices sandwich bread)
• 15 ounces frangelico whole canned
• 0.3 cup cheese grated
• 5 large egg yolk 
• 6 tablespoons flour all-purpose
• 2 large garlic clove finely chopped
• 1.3 teaspoons ground allspice 
• 1.3 teaspoons ground cinnamon 
• 0.3 teaspoon ground cloves 
• 2 pounds lamb 
• 0.8 teaspoon nutmeg grated
• 2 tablespoons olive oil 
• 2 medium onion finely chopped
• 4  thyme sprigs 
• 7 tablespoons butter unsalted
• 7 cups milk whole
• 2 pounds ziti 

Equipment

• bowl
• frying pan
• sauce pan
• oven
• whisk
• pot
• baking pan
• wax paper

Directions

1. Cook onions in oil in a 12-inch heavy skillet over medium heat, stirring frequently, until softened, about 7 minutes.
2. Add garlic and cook, stirring, 1 minute. Increase heat to high, then stir in lamb and cook, stirring occasionally and breaking up any lumps with a fork, until meat starts to brown, about 15 minutes.
3. Meanwhile, drain both cans of tomatoes, reserving juice, and chop.
4. Pour off excess fat from skillet, then stir in tomatoes with their juice, thyme, spices, and 1 1/2 teaspoons salt. Simmer over low heat, partially covered, until some liquid has evaporated but sauce is still moist, about 40 minutes. Discard thyme.
5. Melt butter in a heavy medium pot over medium heat.
6. Whisk in flour, then cook roux, whisking frequently, until pale golden, about 6 minutes.
7. Meanwhile, heat milk in a heavy medium saucepan until just about to boil.
8. Add milk to roux in a stream, whisking constantly until very smooth. Bring sauce to a boil over medium heat, whisking, then cook, whisking, 1 minute.
9. Remove from heat and stir in nutmeg, cheese, and 1 tablespoon salt.
10. Lightly beat yolks in a bowl. Gradually whisk in 2 cups béchamel, then whisk yolk mixture into remaining béchamel in saucepan. Cover with a round of buttered wax paper (buttered side down).
11. Preheat oven to 375°F with rack in middle. Cook ziti in a pasta pot of boiling salted water (3 tablespoons salt for 6 quarts water) until al dente.
12. Drain pasta, then transfer to a large bowl and stir in 1 cup béchamel.
13. Arrange one third of pasta lengthwise in 1 layer in a large (17-by 11-inch) baking pan (about 2 inches deep).
14. Add half of meat sauce (about 3 cups) to baking pan, spreading evenly over pasta.
15. Make another layer of pasta and top with remaining meat sauce, then arrange remaining pasta on top.
16. Spread remaining béchamel (about 6 cups) evenly over top layer of pasta.
17. Stir together bread crumbs and cheese and sprinkle evenly over top of pastitsio.
18. Bake until crumbs are golden brown and sauce is bubbling, about 45 minutes.
19. •Meat sauce can be made 2 days ahead of assembling pastitsio and chilled (covered once cool). Bring to room temperature before using in pastitsio. •Pastitsio can be baked 1 day ahead and chilled (covered once cool). Reheat in a 350°F oven, covered, until heated through, about 45 minutes.