Looks like a papaya seedling to me.

Thanks Carol I thought it might be but the google photos looked a lot ”toothier”. I have two plants that sprouted in my compost. I can't imagine whete the seeds came from.

Yours will get toothy leaves later.

I agree, early leaves can be quite variable.

And some critter may have put those seeds in the pile for you. But it can also take a really long time for them to sprout. I have an area that used to be a compost heap, and hasn't been for a few years, and I'm still getting papaya sprouts there.