The Court of Appeal in UPS v. Superior Court decided that when an employee claims to have been denied both meal AND rest periods in a single day, s/he may recover two of the one-hour penalties made available under Labor Code Section 227.6. So, one penalty is available for however many meal periods are denied in a day, and a separate penalty is available for however many rest periods are denied.
The case is UPS v. Superior Court and the opinion is here.