[Ollie Kenchington]

I am learning AE at the moment and came on to this forum to seek the answer to this exact same question. I am amazed at the long winded work around that is needed to achieve this simple animation!

This is something you can do very easily in Apple’s Motion application. Masks have Transform (inc Rotate) parameters that can by keyframed and interpolated just the same as any other object. It’s a two second job!

I have to say, the more I learn AE, the more I realise how much I prefered Motion!