Thanks very much for this!

So “that takes the cake” in the Urban Dictionary could either be sweetly innocent or a curious case of double irony… whew! Any AmE speakers reading this? What do you think?

If you go ahead with it, your research into irony is bound to be great fun and cause a big think

I don’t think ‘takes the cake’ featured in my idolect before I started learning to speak ‘merican. I’d have most likely said ‘takes the biscuit’.

The thing that seems common to the meaning of both the expressions is ‘the number one’, ‘the utmost’, ‘the most extreme’ but whether they have positive or negative connotations seems to vary a bit to me. ‘Takes the biscuit’ = generally BrE – generally ironic. ‘Takes the cake’ = generally AmE – could be ironic or not.

So I think Macmillan’s definition and example for ‘takes the cake’ would fit the bill pretty well for ‘takes the biscuit’, but I have qualms about it for ‘takes the cake’. Like you, I’d be searching for context, tone of voice, relationship to check.

Might Macmillan have overstepped the mark a bit here and presumed the two varieties correalated more closely than they do? Or possibly my BrE is getting tainted and some other BrE speakers can put us right.