01 - Melt butter in a medium saucepan over medium heat.
02 - Whisk flour into melted butter and cook, stirring constantly, for about 1 minute to form a smooth roux.
03 - Gradually whisk in milk, ensuring no lumps form. Bring to gentle simmer and cook until slightly thickened, about 2–3 minutes.
04 - Reduce heat to low. Stir in Dijon mustard, hot sauce, garlic powder, cayenne pepper (if using), salt, and black pepper until combined.
05 - Gradually add shredded cheddar cheese, stirring constantly until completely melted and sauce is smooth.
06 - Taste sauce and adjust seasoning as needed. Serve immediately while hot.