When you say that you're putting someone on griddle, it means you're subjecting them to intense questioning or interrogation. However, there are other ways to express this idea without using the same old expression repeatedly. You might say that you're putting someone in the hot seat, or that you're grilling them for answers. Alternately, you could say that you're drilling them for information, or that you're putting them under the microscope. Each of these expressions has a slightly different connotation, but they all get the same basic message across in a new and interesting way.