Get a head start on this by prepping the squash the night before. The filling and sauce can also be prepared a day in advance. Don’t let all the steps scare you, it sounds like a lot more work than it actually is.
Sun Oven Squash and Hazelnut Lasagne
(Adapted for the Sun Oven from Gourmet magazine)
For Squash Filling
3 tablespoons butter, melted
1 large onion, chopped
3 pounds butternut squash, peeled, seeded, and cut into chunks
2 cloves garlic, minced
1 teaspoon salt
1/4 teaspoon white pepper
2 tablespoons fresh flat-leaf parsley, chopped
4 teaspoons fresh sage, chopped
1 cup hazelnuts
1 clove garlic, minced
3 tablespoons unsalted butter
5 tablespoons all-purpose flour
5 cups milk
1 bay leaf
1 teaspoon salt
1/8 teaspoon white pepper
For Assembling Lasagne
2 cups fresh mozzarella, grated
1 cup Parmesan cheese, grated
12 sheets no-boil lasagne
Set Sun Oven out to preheat.
Spread the hazelnuts out in one layer on a rimmed baking sheet and toast in the Sun Oven 10 to 15 minutes, until lightly colored and skins are blistered. Wrap hazelnuts in a kitchen towel and let steam 1 minute. Rub hazelnuts in towel to remove loose skins (not all the skin will come off) and cool completely. Roughly chop nuts.
Place butter in a pot large enough to hold the onions and squash. Put the pot in the Sun Oven to melt the butter, 3 to 5 minutes. Add onions, stir to coat. Cover and cook until softened, 20 to 30 minutes. Add squash, garlic, salt, and white pepper. Cover and cook until squash is tender, 45 minutes to 1 hour. Remove from the Sun Oven and stir in parsley, sage, and nuts. Let cool.
Make Sauce while the filling is cooking. Heat butter and garlic in a 3-quart heavy sauce pan over medium-low heat, cook garlic, stirring about 1 minute. Whisk in the flour and cook, whisking, 3 minutes. Add the milk in a steady stream, whisking. Add the bay leaf and bring to a boil, whisking constantly. Reduce heat and simmer, whisking occasionally, about 10 minutes. whisk in salt and white pepper and remove from heat. Discard bay leaf. (If not using immediately cover the surface of the sauce with wax paper.)
Toss cheeses together. Spread 1/2 cup sauce in a buttered 11- by 8- by 2-inch baking dish and cover with 3 pasta sheets. Cover with 2/3 cup sauce and one third of the filling, then sprinkle with a heaping 1/2 cup cheese. Repeat layering 2 more times, beginning with pasta sheets and ending with cheese. Top with remaining 3 pasta sheets, remaining sauce, and remaining cheese.
Cover with buttered aluminum foil and a dark tea towel or a silicone baking lid. Bake in Sun Oven 45 minutes to 1 hour. Take out of Sun Oven, remove foil and let stand 15 to 20 minutes before serving.
Makes 6 servings.