Cook pasta according to package instructions. Drain reserving about 1 cup of the water the pasta was cooked in. Set aside.
Melt butter in a large skillet over medium-low heat. Add onion and cook until soft and translucent. Add the flour and stir 2-4 minutes. Slowly whisk in the milk. Whisk in the Butternut Squash Pasta Sauce.
As sauce thickens add the Gouda, cheddar and 1/2 cup Parmesan cheese. Whisk in the salt, thyme and pepper to taste. Stir until the cheeses are melted and the sauce is smooth.
Add olive oil to another sauté pan. Brown and crumble the sausage. Drain fat.
Combine the pasta, cheese sauce, sausage and spinach. If too thick add a little of reserved water the pasta was cooked in. Stir well.
Grease a 3-quart baking dish. Add the macaroni and cheese mixture.
Toss the bread crumbs with 1 tablespoon melted butter. Sprinkle 1/4 cup Parmesan cheese and bread crumbs over the top of the casserole.
Bake for 25-30 minutes until the sauce bubbles and the bread crumbs are golden. Serve immediately.