Pasta: Cook pasta according to instructions on package.
Sauce: In a microwave safe bowl, combine milk and half and half. Microwave for about 30 seconds, or until warm. In a large saute pan, heat butter over medium until melted. Whisk in the flour and let cook for about a minute. Whisk in warmed milk mixture. Bring to a gentle simmer and let cook for a few minutes, until mixture thickens.
Flavor: Stir in the cheese until melted. Remove from heat and stir in truffle oil, mustard, salt, and pepper. Taste and add more salt as needed.
Assemble: Pour the cheese mixture over the cooked pasta and gently fold together. Serve immediately.
Switch up the cheese by replacing some of the white cheddar with sharp cheddar, gruyere, smoked gouda, or monterey jack.For a crispy topping, spoon prepared mac and cheese into a casserole dish and sprinkle panko breadcrumbs on top. Broil for a few minutes, until golden brown and crispy on top.Store leftovers in an airtight container in the fridge for about 5 days.