4 year old lying

My 4 year old has recently starting lying frequently. At first we didn’t do much (corrected her, saying “that’s called lying and it’s not ok”) but not necessarily enforcing a consequence specifically for the lying because we figured it was pretty innocent at this age. But she went from innocently realizing that lying is a thing to realizing it works and now she is intentionally lying, knowing that she shouldn’t. She also hides around the house or under blankets sneaking behaviors (like eating a snack when we said no). One of the problems is that we don’t always catch it, so she does get away with it sometimes. And another problem is we don’t know how to enforce it in general. And sometimes (unless we catch her in the act) we are only 95% sure that she is lying. We think there should be a stricter consequence for lying than just the thing she’s trying to avoid getting in trouble for. Any advice?