Re: No option to make Hamburger Cake and Taco Casserole.

@BloodyUser0 That's what all help pages say: https://www.carls-sims-4-guide.com/skills/gourmetcooking/ and also in the forums: https://forums.thesims.com/en_US/discussion/803690/how-do-my-sims-get-the-signature-cake-and-the-hamburger-cake

Do your friends have the rest of the DD content ? Maybe a mod that unlocks this stuff ?

I can't really test it as I have the DD and can't really uninstall it, so I have the content.

Here's an overview: http://simcitizens.com/the-sims-4-digital-deluxe-edition-content-overview/

Do you (or your friends) have any other of the recipes listed there ?