01 - Melt butter in a medium saucepan over medium heat. Whisk in flour and cook, stirring constantly, for about 1 minute until mixture forms a smooth paste.
02 - Gradually whisk in milk, ensuring no lumps form. Bring mixture to a gentle simmer and cook for 2-3 minutes until sauce thickens slightly.
03 - Reduce heat to low. Add Dijon mustard, hot sauce, garlic powder, cayenne pepper (if using), salt, and black pepper. Stir thoroughly to combine all seasonings.
04 - Gradually incorporate shredded cheddar cheese, stirring constantly until completely melted and sauce is smooth. Taste and adjust seasoning if desired. Serve immediately while hot.