In a large bowl, stir together the ricotta, spinach, sage, and garlic. In a second large bowl, stir together butternut squash, olive oil, and 6 cups of italian cheese with a generous amount of salt and fresh-cracked pepper.
Spray a 9x13 pan with nonstick cooking spray. Lay three lasagna noodles on the bottom of the pan. Spread half of the spinach mixture on top of the noodles. Sprinkle half of the butternut & cheese mixture on top. Layer three more noodles, then the remaining spinach and butternut squash mixtures. Top with noodles, then sprinkle the remaining 2 cups of cheese on top.
Bake in an oven preheated to 400 degrees for 20-25 minutes, or until the cheese on top is golden brown and the filling is bubbling around the edges.
In a small bowl, toss tgoether the arugula, vinegar, honey & salt and pepper. Serve on top of your lasagna, if desired.