Fill a large pot with salted water and bring it to a boil. Add the diced butternut squash and cook for about 8 minutes until tender but not mushy. Add the elbow macaroni to the same pot and cook according to package instructions until al dente, usually around 7-8 minutes. Drain both the squash and pasta, and set aside.
In a medium saucepan, melt the unsalted butter over medium heat. Once melted, whisk in the all-purpose flour to create a roux. Cook for 1-2 minutes until the mixture turns a light golden color, stirring constantly. Slowly pour in the milk while whisking to avoid lumps. Continue to cook and whisk until the mixture thickens and coats the back of a spoon, about 3-5 minutes.
Reduce the heat to low and stir in the mustard powder, garlic powder, salt, and pepper. Add the shredded cheddar and mozzarella cheeses gradually, stirring continuously until melted and smooth. Then, stir in the cooked butternut squash, mashing some pieces lightly with the back of a spoon to incorporate them into the sauce and create a velvety texture.
Add the cooked elbow macaroni and chopped turkey bacon into the cheese and squash mixture. Stir gently to combine everything evenly.
In a small skillet, heat the olive oil over medium heat. Add the breadcrumbs and chopped fresh sage, stirring frequently until the crumbs are golden brown and fragrant, about 3-5 minutes. Be careful not to burn them.
Transfer the mac and cheese mixture into a greased baking dish. Evenly sprinkle the sage crumbs over the top. Bake in a preheated oven at 350°F (175°C) for 15-20 minutes, or until the topping is crisp and the sauce is bubbling around the edges.
Let the dish cool for a few minutes before serving. This Butternut Squash Mac and Cheese with Sage Crumbs pairs beautifully with a simple green salad or roasted vegetables for a complete meal.
