Ribbons of chickpea noodles add a delightfully hearty texture to this butternut squash lasagna.
Preheat the oven to 400 degrees F. Prepare a rimmed baking sheet with parchment paper to roast the squash. Also, prepare an 8 x 12 inch baking dish with olive oil and set aside for the lasagna.
Place the squash cut side down on the prepared baking sheet and roast in the oven for 45 minutes or until very tender.
Meanwhile, to make the caramelized onions, add a drizzle of olive oil (about 2 tsp.) to a large skillet. Once the oil is shimmering, add the onions and a pinch of sea salt. Toss the onions in the oil and spread the onions evenly in the pan with a spatula, cover, and scrape the pan every 5 minutes to ensure the onions start to brown and become very tender. Continue to scrape the pan with your spatula and cook until the onions are a deep brown color. Add some water or more olive oil if your onions start to dry out. Allow the onions to cook for 30 minutes or until the onions are browned and very tender.
Make the walnut ricotta by combining all the Walnut Ricotta ingredients in a mini food processor and puree until very thick and creamy.
Remove the squash from the oven and set aside to cool for 5 minutes or until it's cool enough to touch. Using a spoon, scrape out the squash flesh and transfer it to a large food processor with the sea salt and cumin. Puree until the squash is creamy. Season to taste with the salt and cumin.
Lower the oven to 350 degrees F. Coat bottom of the prepared baking dish with the squash purée then a layer of the lasagna noodles followed by the ricotta and onions and continue to layer until you use up all of the ingredients. The top layer should be the squash puree. Sprinkle the cumin over the top layer and add a few dollops of the walnut ricotta on top, if desired.
Transfer the lasagna to the oven at the lower heat of 350 degrees F covered with parchment paper for 1 hour or until the noodles are tender. Remove the parchment paper and bake for another 10 minutes. Remove the lasagna from oven and set aside for 10 minutes before serving. Serve warm.
Store leftovers in a sealed glass container in the refrigerator for up to 3 days or in the freezer for up to 1 month.