Step 1

Preheat the oven to 425 degrees F. Peel the butternut squash and chop the flesh into cubes. Toss the cubed squash in 1-2 tablespoons olive oil and roast in the oven for 15-20 minutes until the squash is fork tender. Scrape the warm squash into a bowl and mash with a fork until smooth. Let it cool to warm room temperature before using in the recipe (this step can be done 2-3 days in advance and the cooked, mashed squash can be stored, covered, in the refrigerator). Reduce the oven temperature to 400 degrees F.

Step 2

Cook the jumbo pasta shells according to package directions and drain. In a medium bowl, combine the squash, ricotta cheese, Parmesan, garlic, spinach, egg, salt and pepper and fresh lemon zest. Stir well. Stuff the cooked pasta shells with the squash/ricotta mixture and place them in a lightly greased 9X13-inch baking dish (depending on how full you fill the shells, you may not use all of them). Bake the shells for 18-20 minutes, until they are hot all the way through.

Step 3

While the shells are making, prepare the brown butter sauce by melting the butter in a saucepan or skillet over medium-low heat until the butter is golden brown, about 10-12 minutes. Watch carefully as the butter can go from browned to burned in a short time. Add the sage leaves and cook until the leaves are slightly crisp (the butter should be hot and bubbly when adding the leaves so that the sage cooks quickly). Remove the pan from the heat and squeeze in the juice of 1 lemon.

Step 4

Drizzle the sauce over the cooked shells and top with additional grated Parmesan, if desired. Serve the shells with 1-2 crisp sage leaves on top.