Mix together all ingredients for the Ricotta layer. Place in the refrigerator until you’re ready to assemble.

Grate the mozzarella and set aside in the refrigerator.

Melt the butter in a stockpot over medium-high heat. Once melted, whisk-in the flour and continue to whisk for about 2 minutes. Then, whisk in the milk and continue to whisk until combined… about 2 minutes. Next, whisk-in the pumpkin puree, nutmeg, salt, pepper, and turn off the heat.

Add the sausage to a large skillet over medium-high heat. Break apart and sauté until starting to brown. Add the yellow onion, garlic, and continue to sauté until softened. About 5 more minutes.

Spread 1 cup of the pumpkin béchamel sauce in a 9x13 greased casserole dish. Top with 4 lasagna noodles, slightly overlapping. Next layer with 1/2 ricotta cheese mixture, 1/2 the sausage, about 1 cup of cheese (I like to alternate layers with the provolone and mozzarella), and then 1 cup pumpkin béchamel sauce. Repeat these layers one more time. Finish with 4 noodles on top, remaining pumpkin béchamel, and remaining cheeses.

Cover with foil that's been sprayed on the interior side with cooking spray, then bake for 45 minutes in a preheated 350F oven.

Remove foil and bake for an additional 15 minutes, or until browned and bubbly. If desired, broil at the end for 2 minutes.

Allow the lasagna to rest for at least 10 - 15 minutes before cutting and serving. Garnish each lasagna slice with parmesan cheese, chopped parsley, and optional red pepper flakes.