Squash Hazelnut Lasagna

'Tis the season for butternut squash! I made this lasagna for the pre-marathon dinner party last weekend and my friend Zach claims it is a big part of the reason he qualified for Boston. Congrats to Zach and everyone else who completed a marathon this fall!

This recipe was modified from one I found on epicurious. http://www.epicurious.com/recipes/food/views/Butternut-Squash-and-Hazelnut-Lasagne-105911

Filling:
1 large onion, chopped
3 tablespoons unsalted butter
3 lb butternut squash, peeled, seeded, and cut into 1/2-inch pieces
3 cloves garlic, chopped small
1 teaspoon salt
1/4 teaspoon pepper
2 tablespoons chopped fresh flat-leaf parsley
4 teaspoons chopped fresh sage
1 cup hazelnuts

Sauce:
3 cloves garlic, chopped small
3 tablespoons unsalted butter
5 tablespoons all-purpose flour
5 cups milk
1 teaspoon salt
1/8 teaspoon pepper

Assembly:
3 cups shredded mozzarella
1 package lasagna sheets, cooked as instructed

Make filling:

1. Saute onion in butter in a deep 12-inch heavy skillet over moderate heat, stirring occasionally, until golden, about 10 minutes.
2. Add squash, garlic, salt, and pepper and cook, stirring occasionally, until squash is just tender, about 15 minutes.
3. While the squash is cooking, toast the hazelnuts. After they have cooled slightly, wrap the nuts in a kitchen towel and rub the skins off. Coarsely chop the nuts.
4. Remove from heat and stir in parsley, sage, and nuts. Cool filling.

Make sauce:

1. Saute garlic in butter in a 3-quart heavy saucepan over moderately low heat, stirring, 1 minute.
2. Whisk in flour and cook roux, whisking, 3 minutes.
3. Whisk in milk and bring to a boil, whisking constantly, then reduce heat and simmer, whisking occasionally, 10 minutes.
4. Whisk in salt and white pepper and remove from heat.

Assemble lasagna:

1. Preheat oven to 425°F.
2. Spread 1/2 cup sauce in a 13- by 9- by 2-inch glass baking dish (or other shallow 3-quart baking dish) and cover with 3 pasta sheets, leaving spaces between sheets.
3. Spread with 2/3 cup sauce and one third of filling, then sprinkle with a heaping 1/2 cup cheese.
4. Repeat layering 2 more times, beginning with pasta sheets and ending with cheese.
5. Top with remaining 3 pasta sheets, remaining sauce, and remaining cheese.
6. Tightly cover baking dish with buttered foil and bake lasagna in middle of oven 30 minutes.
7. Remove foil and bake until golden and bubbling, 10 to 15 minutes more. Let lasagna stand 15 to 20 minutes before serving.

To travel with the lasagna I baked it for 30 minutes (covered) and then let it cool and stored it in the fridge. I used the remaining 10-15 minutes baking time to reheat the lasagna before serving. Since it was cold to start it probably took more like 30-45 minutes for the lasagna to get golden and bubbly.