Boil Pasta: Bring a large pot of salted water to a rolling boil. Add macaroni or cavatappi pasta and boil until al dente according to package instructions (about 7 to 8 minutes). Drain well, drizzle with 1 teaspoon olive oil, and set aside.

Melt Butter & Cook Roux: In a large Dutch oven or deep skillet, melt the butter over medium heat. Whisk in the flour and cook for 1 to 2 minutes until golden, bubbly, and fragrant to eliminate the raw flour taste.

Whisk in Warm Dairy: Gradually pour in the warm whole milk and heavy cream in a steady stream while whisking continuously to prevent lumps. Cook for 4 to 5 minutes, whisking constantly, until the sauce thickens to coat the back of a spoon.

Season: Whisk in garlic powder, onion powder, dry mustard, smoked paprika, sea salt, and black pepper until completely smooth.

Melt Cheese Off Heat: Slide the pan completely off the direct heat source. Add freshly grated sharp white cheddar and Gruyere in three gradual additions, stirring gently until fully melted and glossy.

Fold in Pasta: Add the drained warm pasta into the silky cheese sauce. Fold gently until every noodle is luxuriously coated. If the sauce is too thick, stir in 2-3 tablespoons of warm milk or starchy pasta water.

Rest & Garnish: Let the mac and cheese sit off the heat for 2 minutes to settle. Garnish generously with fresh snipped chives and serve immediately warm!