• Step 1: Bring a large pot of salted water to a boil. Cook the elbow macaroni according to package instructions until al dente, about 7-9 minutes. Drain the pasta and set aside.
• Step 2: In a large saucepan, melt the butter over medium heat. Whisk in the flour and cook for 1-2 minutes, stirring constantly, to create a roux.
• Step 3: Gradually pour in the milk, whisking continuously to prevent lumps from forming. Bring the mixture to a simmer and cook, stirring occasionally, until thickened, about 5-7 minutes.
• Step 4: Remove the saucepan from heat and stir in the shredded cheddar cheese, diced green chilies, cumin, garlic powder, onion powder, and cayenne pepper (if using). Season with salt and black pepper to taste.
• Step 5: Add the cooked macaroni to the cheese sauce and stir to combine. Serve hot, garnished with additional green chilies or chopped fresh parsley, if desired.