Preheat oven to 425 F. Toss squash cubes with olive oil and a sprinkle of salt. Roast for 20 minutes or until tender. Place cooked squash in a bowl and mash well with a fork. Set aside.

Reduce oven temperature to 375 F.

While the squash is roasting, prepare pasta according to box instructions. Drain.

Prepare the butter sauce while pasta is cooking by melting butter in a skillet over medium low heat until golden brown; about 10 minutes. Add sage leaves and cook until crisp. Remove the pan from the burner and add lemon juice. Set aside.

In a large bowl, combine ricotta, egg, parmesan, garlic, spinach, salt, pepper and lemon zest. Stir well. Add squash to bowl and stir until combined. Combine drained pasta with squash mixture and stir well. Place pasta/squash mixture in large baking dish.

Drizzle the butter over the pasta and bake 375 for 25 minutes.