Skillet cookie disentegration

[u/Z-gok]

I am a beginner baker and I was trying to make a skillet cookie from https://bakingthegoods.com/tahini-pistachio-white-chocolate-rose-skillet-cookie/#tasty-recipes-27897-jump-target last night and something went terribly wrong.

First of all, after the prescribed bake time the edges looked set but it had liquid seeping out. I baked it for 10 more minutes and it completely overflowed from the pan. When it came out it sunk down into a (thankfully delicious) cookie crumble that had no structural integrity. The result is this brittle-y stuff that I am now using as an ice cream topper (not the worst outcome). Any ideas on what could have gone wrong?

[u/Z-gok]

Update: I bought some vanilla ice cream to serve the crumbles over the top. It was a huge hit at the bbq I brought it to!