Preheat your oven to 350°F (175°C). Generously grease a large 9×13-inch baking dish or 12-inch cast-iron skillet with 1–2 tablespoons of unsalted butter, ensuring every corner is coated to prevent sticking.

Bring a large pot of water to a rolling boil. Add 1–2 teaspoons chicken bouillon powder and 1 teaspoon salt to infuse flavor directly into the pasta. Add the elbow macaroni and cook for 7–10 minutes until al dente (still slightly firm to the bite). Drain thoroughly and immediately rinse with cold water to halt the cooking process and prevent mushiness. Set aside.

In a large pot over medium heat, pour in the 2 cups of whole milk and warm it gently (do not let it boil). Add the softened cream cheese chunks and stir continuously until mostly melted and incorporated into the milk, creating a smooth base.

Add garlic powder, onion powder, dry mustard powder, white pepper, salt, black pepper, and the optional teaspoon of chicken bouillon powder to the milk mixture. Stir well to distribute all seasonings evenly throughout the sauce.

Reduce heat to low. Gradually add half of the shredded sharp cheddar, half of the white cheddar, and half of the pepper jack cheese to the seasoned milk. Stir constantly in a figure-eight motion until the cheese completely melts into a smooth, velvety sauce. Taste and adjust seasoning if needed.

Transfer the cooked, drained macaroni to a very large mixing bowl (or return to the emptied pasta pot if large enough). Pour the hot cheese sauce over the pasta. Add most of the grated Parmesan cheese (reserve about 2–3 tablespoons for the topping). Gently fold and stir until every piece of pasta is thoroughly coated in the creamy sauce.

Pour the sauced macaroni into your prepared baking dish or cast-iron skillet. Use a spatula to spread it evenly across the dish, creating a level surface.

Generously cover the entire top surface with the remaining sharp cheddar, white cheddar, pepper jack, and the reserved Parmesan cheese. This creates that signature golden, bubbly crust.

Place the dish on the center rack and bake uncovered at 350°F for 25–30 minutes, or until the top is golden brown, bubbly, and slightly browned in spots with crispy edges.

Remove from the oven and let the white cheddar mac and cheese rest for 5–10 minutes. This resting period allows the sauce to set and become even creamier. Serve hot and enjoy your homemade copycat chilis white cheddar mac and cheese!