1. Butternut Squash Filling: Peel, seed and cut the squash (discarding the ends) into half-inch cubes. Heat the oil and melt the butter in a large skillet over medium-high heat. Add the squash and toss to coat. Sprinkle with salt and pepper. Pour the water into the skillet, cover and simmer over medium heat until the squash is tender, stirring occasionally, about 20 minutes. Meanwhile, in a food processor, finely crush the amaretti cookies. Add the amaretti powder to the squash and thoroughly mix. Season to taste with more salt and pepper, and set aside.

2. Béchamel Sauce: Melt the butter in a 2-qt. saucepan over medium heat. Add the flour and whisk for 1 minute until just golden and fragrant. Gradually whisk in the milk. Bring to a boil over medium-high heat. Reduce the heat to medium and simmer until the sauce thickens slightly, whisking often, about 5 minutes. Whisk in the nutmeg. Cool slightly. Transfer some of the sauce to the food processor. Add the basil and garlic, then blend until smooth. Return the basil sauce to the sauce in the pan and whisk to blend thoroughly. Season with salt and pepper.

3. Position the rack in the center of the oven and preheat to 375º. Lightly butter a 13 by 9 by 2-inch glass baking dish. In a small bowl, mix the ricotta cheese, Parmesan and egg together. Season with salt.

4. To assemble, spread 3/4 cup of the basil béchamel sauce over the prepared baking dish. Arrange 3 lasagna noodles on the bottom of the pan. Spread 1/3 of the ricotta mixture over the noodles. Spread 1/3 of the squash filling over the noodles. Sprinkle with 1/2 cup of mozzarella cheese. Drizzle 1/2 cup of sauce over the noodles. Repeat layering 3 more times.

5. Tightly cover the baking dish with foil and bake the lasagna for 40 minutes. Remove the foil and sprinkle the remaining mozzarella cheese over the lasagna. Continue baking uncovered until the sauce bubbles and the top is golden, 15 minutes longer. Let the lasagna stand for 20 minutes before serving.


Notes: Amaretti cookies are very dry, crunchy Italian cookies that are not too sweet and have a very strong almond taste. You can find these in gourmet grocery stores. Do not substitute other cookies, instead, add 1/4 tsp almond extract and a pinch of nutmeg.