100% YW Pulla -- AMAZING oven spring!!!

I am SO glad to have an active yeast water! The leavening properties of YW are pretty amazing. I have updated my recipe for this loaf after discovering a few errors in an older YW Pulla post, now deleted.
Here is the proofed loaf on the peel, ready to bake:
After baking for 29 minutes, steam for the first 12:
Levain:
50g yeast water
50g strong bread flour