01 - In a medium saucepan, melt the butter over medium heat.
02 - Whisk in the flour and cook for 1 minute, stirring constantly, to form a roux.
03 - Slowly pour in the milk, whisking until smooth. Bring to a gentle simmer and cook for 2–3 minutes until slightly thickened.
04 - Reduce heat to low. Add the cheddar and mozzarella cheeses, stirring until completely melted and smooth.
05 - Stir in garlic powder, onion powder, smoked paprika, pepper, and salt.
06 - Taste and adjust seasoning as needed. Serve warm over fries or as a dip.