Preheat oven to 400 degrees.

Line a 9x13 cookie sheet with parchment paper.

Using a very sharp knife, split the pumpkin/butternut squash in half.

Rub the pumpkin/squash halves all over with 3 tablespoons of olive oil.

Place the pumpkin/squash halves, cut side down, on the cookie sheet and roast between 45 minutes to 1 hour, until skin has darkened and the pumpkin/squash is really fork tender. Remove from the oven and set aside to cool/until cool enough to safely handle.

When the pumpkin/squash has cooled, remove the seeds and the skin. Place the pumpkin flesh in a bowl and mash with a fork until smooth. Set aside.

Fill a 4 quart pot with water, a pinch of kosher salt, and a tablespoon of olive oil,.

Place the pot over a medium-high heat to a boil.

Add the pasta and cook as directed by the instructions on the package until al dente. Drain the pasta in a colander, and rinse with cool water. Set aside. Rinse the pasta pot with water and wipe clean. Place back on the stove top.

Melt 3 tablespoons of butter in the 4 quart pot over medium heat until slightly shimmering. Continue to monitor the butter until it turns light brown and begins to smell nutty.

Add the minced garlic and sage. Stir and cook until the garlic is slightly golden and both garlic and sage are fragrant, about 1 minute.

Add the flour to the pot and stir until there is no visible white flour left on the bottom of the pot, about 30 seconds.

While stirring, slowly add the milk and lower the heat to a simmer. Add the garlic powder, sage powder, and nutmeg. Stir continuously until the milk has reduced and the spoon can draw clean lines to the bottom of the pot. This should take about a minute.

Add 6 oz. of grated cheese and stir continuously until the cheese has melted. Add the pumpkin/squash and stir well to until incorporate.

Add the spinach to the pot, mix well to combine.

In a large mixing bowl, add the cooked pasta and the pumpkin mixture. Carefully mix until the pasta and sauce are evenly distributed.

Butter a 11x8 inch (2.5 quart) gratin dish

Pour the pasta mixture into the gratin dish and smooth the top.

Sprinkle the top of the pasta with 1.5 oz. cheddar cheese and pecorino romano cheese.

Sprinkle the panko and the four shredded sage leaves over the top and lightly drizzle the olive oil over the top.

Tightly cover the gratin well with with aluminum foil, making sure to tent it so the foil does not touch the pasta (otherwise the foil will stick when baking). Place the gratin dish on a cookie sheet and bake in the oven for 40 minutes.

Remove the foil from the gratin dish and bake for another 8-10 minutes until the cheese is melted. Remove from the oven.

Turn the oven and switch the broiler on to medium. Place the gratin dish (with the cookie sheet) under the broiler for about 1-2 minutes until the cheese has golden bits and the edges get a but crunchy. REMEMBER to watch the dish while under the broiler, it can turn from golden to burnt in an instant!

Remove from the oven and allow the baked pasta to cook for 5 minutes before serving.