The rabbit should be golden.

But otherwise still got a grin out of me

Dad joke award.

I let down my heir by telling dad jokes in public

I think the pun is meant to be "let down your hair/hare", even though it is clearly a white rabbit.

It's a pune, as Sir Terry would have called it. A play on words in the english languages, Rapunzel has been asked to let down her hair, but that sounds the same as hare, which is a lagamorph, like a bunny.

...for that i've groan.

that's not the half of it, at dinner she served her pet cat

♪ One pun makes for laughter
And one pun makes you groan ♫ (apologies to Jefferson Airplane)

🫨

Def not a hare.

Most welcome, mon ami.