1/4 cup butter
1/4 cup all-purpose flour
2 cups milk
1/4 teaspoon salt
1 teaspoon Worcestershire sauce
2 cups (8 ounces) shredded sharp Cheddar cheese
1 (4-ounce) jar diced pimiento, drained
Melt butter in a heavy saucepan over medium heat; add flour, stirring until smooth. Cook, stirring constantly, 1 minute.
Add milk gradually; cook, stirring constantly, until mixture is thickened and bubbly. Stir in salt and remaining ingredients.