I wouldn't "ignore"exactly, but acknowledge her feelings (I can see you are angry/sad because... I am here if/when you are ready for a cuddle) then just stay near by and wait it out, reminding her occasionally they you are available for a cuddle if she wants one.

It depends on the kind if tantrum too, if it's more physical I'd give her space but if it's emotional I'd hold her until she calms down.

It's hard because everyones child reacts differently, I think you just need to do what feels right and be open to trying new things when, inevitably, the old tactics stop working.