COOK IT.
Set the butternut squash on a cutting board, then cut in half. [Depending on the weight of the butternut squash, only half of the squash will need to be used.] Scoop out the seeds with a spoon and discard. Score diagonal lines into the surface of each squash half to form a diamond-like pattern, about ¼” deep. Brush with olive oil, then season with Maple Walnut.
Transfer seasoned squash to the grill, skin-side down, and cook for 1 to 1 ½ hours. Remove from the grill and set aside to cool for 15 minutes.
Meanwhile, heat the olive oil in a small saucepan. Add the onion and sauté for 2 minutes, then add in garlic and sauté for 1 minute, until fragrant. Remove from the heat.
Scoop out the flesh of the squash into the bowl of a food processor, or simply peel off the skin using the back of a spoon. Add the sautéed onion and garlic. Season with Maple Walnut, then process on low for 1 minute. Add the egg yolk, then process another minute, until smooth, scraping down the sides if needed. Return the puree to the saucepan, or a mixing bowl. Set aside.
Whisk the egg white in a small bowl, then set aside.
On a flat work surface, lay out 8 to 12 wonton wrappers. Brush the edges of each wrapper with the beaten egg white, then place a ½ tablespoon of squash filling in the middle. Top each with another wrapper, then press along the edges to properly seal.
Add water to a deep skillet or pot, then bring to a boil. Cook ravioli, in batches, for 2 minutes, then transfer to a greased sheet tray.
Place a skillet on the grill, and melt the butter. Add sage leaves and sauté for 2 minutes, stirring often. Add the ravioli, and gently coat in sage butter.
Transfer ravioli to a plate, and sprinkle with parmesan cheese. Serve warm.