I don't know about the bundt cake with the pudding inside, but I used to make a bundt cake that has a pretty solid custard on top. After pouring the batter in the cake pan, I would pour the custard into the pan, through the cake batter, and it would fall through, winding up at the bottom of the pan; top of the cake, once turned right-side up.
Yes, I'm quoting my own post, but I thought I'd share a photo of the above-mentioned cake:
No, I didn't make it, my brother's wife did. He simply carried it from his kitchen to his truck, then from his truck to the office break room.
He's probably worn out by the exertion.
The stuff on the lower-left is some kind of chocolate thing, that I'm wondering if I should've eaten, now that someone pointed out a certain ingredient possibility. The stuff at the top, is a slice of store-bought cheesecake. I'm not the only one that brought in a pie in a box.
