2cupsfreshly grated melty flavorful cheesesuch as cheddar, gruyere, provolone, fontina, gouda, or a mix, divided (about 8 ounces; I used half extra-sharp white cheddar and half provolone)
Prep the cauliflower: Cut the cauliflower into large florets, then shred with the large side of a box grater. For quicker grating, place cut florets in a large food processor fitted with a steel blade, then pulse until the cauliflower resembles small grains of rice. The smaller the pieces of cauliflower, the more it will blend in with the mac and cheese. You will have about 4 cups of riced cauliflower total.
Place the pasta, cauliflower, 3 1/2 cups water, butter, and salt in a 6-quart or larger Instant Pot or pressure cooker. Stir well. Set to cook on high pressure (manual) for 4 minutes.
As soon as the timer goes off, release the steam using the valve on top. Dot the cream cheese in small pieces over the top, then gently stir in the shredded cheese, 8 ounces evaporated milk, garlic powder, and black pepper. If the mac and cheese seems too thick, stir in a little more evaporated milk or water, until your desired consistency is reached. Taste and add additional salt and pepper as desired (I added one generous additional pinch salt). Serve hot.
Notes
To make in a slow cooker (NOTE: I have not yet tried this, so it would be an experiment! This is my best-guess method.): To the slow cooker, add the pasta, cauliflower, 8 ounces evaporated milk, 3 1/2 cups water, salt, garlic powder, and pepper. Cook on low for 3 to 4 hours, until most of the liquid is absorbed. Check periodically and if the noodles seem too dry, add a bit of water as needed. Stir in the shredded cheese and cream cheese. Taste and adjust seasoning as desired.
I don't recommend gluten-free pasta, as it breaks down and becomes very gummy.