Preheat oven to 425 degrees F.
Using a sharp kitchen knife, remove the tops of the acorn squash. Remove the seeds. Rub the insides of the squash with olive oil and season liberally with salt, pepper and garlic powder (eyeball it). Place the acorn squash on a parchment lined baking sheet with sides. Roast the squash in the oven for 25-30 minutes.
While the squash is roasting start on the mac and cheese. Bring a large pot of salted water to a boil and cook the pasta according to the package directions until al dente. Strain and set aside.
Melt the 6 tablespoon of butter in a large sauce pan over medium high heat. Cook the onions for 10 minutes, stirring often, until they turn translucent and begin to caramelize. Add the chopped sage and cook for an additional minute until fragrant. Sprinkle the flour over the onion and stir until the flour is fully mixed into the onions, cooking an additional minute. Add the white wine. Gradually whisk in the whole milk and cream.
Bring the sauce to a gentle boil and cook for 2-3 minutes until it begins to thicken. Turn the heat down to medium low and add the garlic powder and a pinch of nutmeg. Add the gouda, gruyere and white cheddar, stirring until the cheeses are melted. Season to taste with salt and pepper. Add the cooked pasta and gently toss to coat.
Reduce the oven temperature to 400 degrees F. Melt the remaining tablespoon of butter in a small sauce pan and add the breadcrumbs. Stuff the mac and cheese into the squash, top with buttered breadcrumbs and transfer to the oven. Bake for 15-20 minutes until the mac and cheese begins to bubble and the tops are lightly browned. Serve squash bowls and ENJOY!