Salted Butter (3 1/2 Tbsp)
in a saucepan over medium heat.
All-Purpose Flour (1/3 cup)
and whisk rapidly to combine.
Reduce to low heat and continue to whisk as the mixture cooks into a paste (roux), about two minutes. Be careful not to let it burn.
Slowly begin incorporating
Milk (2 cups)
, a splash at a time, whisking continuously.
Continue to add milk and cook until the mixture forms a paste, about ten minutes.
Once mixture is smooth and thick, take off heat.
Mature Cheddar Cheese (2/3 cup)
Salt (to taste)
Ground Black Pepper (to taste)