Combine the egg and milk in a large bowl and add a pinch of salt. Whisk in the flour and refrigerate, covered, for at least 30 minutes.
Heat about 4 cups of oil in a large pot to 365 degrees F.
Dunk the frozen candy bars into the chilled batter, and then gently drop them, in batches into the oil. Cook just until light golden in color, then remove them to a brown paper bag to drain and cool for at least 1 minute.