Cook Elbow Macaroni (16 ounce) according to instructions, strain, and set aside.
Make a roux by whisking together Butter (4 tablespoon) and All-Purpose Flour (1/4 cup) over low heat in a Dutch Oven.
Add Milk (1 cup), Half and Half (1/2 cup), Chili Powder (1 teaspoon), Onion Powder (1/2 teaspoon), Ground Nutmeg (1/4 teaspoon), and about 2/3 of your shredded Sharp Cheddar Cheese (8 ounce) and Monterey Jack Cheese (8 ounce). Whisk over low heat until smooth.
Add cooked macaroni and mix until coated evenly with cheese sauce. Add more half & half if needed. It should be pretty loose and easy to stir. Taste and add Salt (to taste) or Ground Black Pepper (to taste) if needed.
Remove from heat and stir in the rest of your cheese. Garnish with Fresh Parsley (1 handful) for some freshness and enjoy!