1. Whisk milk and flour together in a medium saucepan; bring to boil over medium heat, stirring frequently. Remove from heat; add mustard.
2. For a smooth dressing, add all of the cheese and stir until melted. Or, for a chunkier dressing, reserve ¼ cup (50 mL) of the cheese to add to cooled dressing. Let cool to room temperature.
3. Whisk in mayonnaise; season to taste. For optimum flavour, serve at room temperature, but store in refrigerator.

Chef Tips: 

• When shredding cheese, to prevent sticking, moisten shredder with water, or lightly spray with cooking spray.
• If desired, add crumbled crisp-cooked bacon, or finely chopped chives to dressing.