Well, you're going to want some tri-n-butyl phosphate, nitric acid, peroxide for the wash, some lackeys (seriously, you do not want to do this yourself), and an ominous volcano lair hideout. Don't worry about the oven temperature, you probably won't be able to exceed the boiling point. I know uni-taskers are so last year, but you're really going to want a centrifuge cascade for the refining. Also, I would suggest lead shielding and tele-operated "cooking" gear. That will get you the closest thing to yellowcake without "baking" if your mold looks like this.

Now, if you're just making a prop to show off a baking mold, I think /u/win3aboutit 's suggestion is pretty solid if you plan to eat it although at that point I'd probably just use food-safe materials and ditch the uranium refining entirely. If it's for a display piece you could buy non-shrinking silicone molding materials to make a high-detail negative then cover the mold in fondant so you can't tell that it's not a cake.