Calorie guess?

I cannot find this in the MFP database at all, or online. And I suck at guessing calories. And I really want to eat this and at least log something that seems reasonable enough as a calorie amount.
Nowhere on the package does it have the nutritional information, or a website to go check it out.

Basically, it's from the bakery section at Walmart.
It's a Happy Birthday chocolate chip cookie cake with chocolate frosting.

How many calories do you assume would be in a slice that is this size (also the cookie I have is about this thick, too)