2/3cupwhole plain Greek yogurtdo not use low fat or fat free or it may curdle
Chopped fresh chivesoptional, for serving
For the Topping:
1/4cupgrated Parmesan cheeseabout 3/4 ounce
1 1/2teaspoonsextra-virgin olive oil
Preheat the oven to 400 degrees F. Coat a 9x13-inch baking dish with nonstick spray.
Steam the squash according to package instructions until fork tender (if cooking fresh squash, bring a large pot of water boil. Add squash and boil until tender, 4-6 minutes.). Drain the squash, then transfer to a blender.
Meanwhile, in a Dutch oven or similar deep, wide pot, cook the bacon over medium-low for 8 to 10 minutes, until the fat is rendered (don’t rush it or the bacon will burn). With a slotted spoon, transfer the bacon to a paper towel-lined plate and lightly pat dry. Discard all but 1/2 tablespoon drippings from the pot.
Return the pot to medium-low heat. Add the shallot and sauté until softened, about 5 minutes.
In a separate pot, cook the pasta until nearly al dente. It shouldn’t be completely crunchy but when you taste it, it should still be too firm to eat. Drain and set aside.
In a small bowl, stir together the topping ingredients: Parmesan, panko, and olive oil. Set aside.
Add the milk and broth to the blender with the squash. Blend until smooth, then pour into the pot with the shallot. Add the mustard, salt, nutmeg, and cayenne. Stir until combined.
Bring the sauce to a gentle boil. Reduce the heat as needed to maintain a steady simmer. Simmer, stirring very often to prevent sticking, until the sauce is thickened, about 5 minutes. Remove from the heat and let cool 3 minutes.
Whisk in the cheddar, Parmesan, and Greek yogurt until smooth. Taste and add additional seasoning as desired.
Gently stir the noodles and bacon into the sauce.
Scoop into the prepared baking dish (it will seem very saucy). Sprinkle the topping mixture over the top.
Bake the butternut squash mac and cheese for 25 minutes, then turn the oven to broil. Broil for 2 to 3 minutes until the Panko is lightly browned. DO NOT walk away or the topping may burn when you let expect it. Sprinkle with fresh chives. Let cool a few minutes, then enjoy hot.
*For a vegetarian butternut squash mac and cheese, omit the bacon. Sauté the shallot in 1/2 tablespoon olive oil instead of the bacon drippings.