I just put in dog bakery houston in google and there were several listed. Here is one that has the little round cakes.
Jackon's Gourmet Dog Bakery-Birthday Cakes & Dog Treats - Houston, TX
Here's Bone Appetite
Bone Appetit: Posh pet bakery puts on the dog for party animals - Houston Business Journal:
Here's one in Old Town Spring:
woofpetbakery.com
Good luck!!