Roast the garlic: Place a rack in the center of your oven and preheat to 375°F. Slice the top off of the garlic head and drizzle the exposed tops of the garlic cloves with olive oil. Wrap tightly with foil and roast on a baking sheet, in a baking dish, or right on the rack of your oven. Roast for 30-45 minutes, until the cloves are golden and caramelized when you check underneath the foil. Keep the oven on to bake the mac and cheese later.

Cook the pasta: While the garlic roasts, fill a large pot with water and a healthy sprinkling of sea salt. Bring to a boil, then add the pasta. Boil for about 5 minutes, until they are quite al dente. (Remember it's okay if they're slightly firm because they will cook more in the oven.) Transfer to a colander to drain the pasta, then transfer to a 9” x 13” baking dish. (This size fits this amount of mac and cheese just perfectly, but you could use another desired baking vessel the same size or a bit larger.) Set aside.

Blend the sauce: In a high-speed blender, add the cashews and water, then blend until smooth and creamy. This should take a minute or two. Squeeze in the roasted cloves of garlic, then add in the chopped cheeses, butter, miso, mustard powder, cayenne, and nutmeg. Start by blending on low and gradually turn up the speed until you are left with a smooth and creamy sauce. Scrape down the sides and move everything around as needed. (Please work with your blender, help it out and don’t give it an aneurysm.) If using a smaller blender, divide the cashew cream in half and try blending the sauce in two separate batches.

Combine and bake: Pour the blended cheese sauce over the noodles in the baking dish. Mix well. Bake in the oven, uncovered, for about 30 minutes, until the edges are slightly golden and the cheese is thoroughly melted. For the last few minutes, turn your oven's broiler on and place the baking dish on the top shelf. Watch it closely and remove it once you've achieved your desired level of golden brown.

Finish and serve: Remove the mac and cheese from the oven, pour on the truffle oil, and stir with a large spoon. Let stand for 10 minutes. Serve immediately.