Melt 2 tablespoons salted butter in a saucepan over medium-high heat.
Whisk in 2 tablespoons all-purpose flour and ⅛ teaspoon cayenne pepper and cook 1 to 2 minutes.
Slowly whisk in 1 cup milk and bring to a simmer over medium-high heat.
Reduce the heat to low and add in 8 ounces shredded sharp cheddar cheese.
Stir until cheese is melted and smooth.
