I’m trying to identify a specific organ arrangement of Hyfrydol. Can anyone help me with who arranged it?

It’s the one that starts on a held lone C followed by another held C an octave below. Then it turns into intellectually stimulating mass dissonance with the hyfrydol theme buried in it. It was arranged by a man (I saw the music once sitting out four years ago, but I can’t remember the name on it other than it was a man’s name.)

Anyone know which one I’m referring to based on my vague description?