Several food establishments have had their “secret” menus exposed on social media. From Starbucks to Chipolte to Wendy’s, some restaurants offer items only on the down low.

One secret restaurant hack that you probably had absolutely no idea about was the McDonald’s $9 birthday sheet cake.

Yes, for just 9 bucks, you can order an entire sheet cake that even comes with Ronald McDonald decoration on the cake. This item is so secret that most McDonald’s employees don’t even know it exists. However — thanks to TikTok — the cat is officially out of the bag.

While the cake can’t be found on McDonald’s online menu, a simple search for “birthday cake” on the site will yield two results: Ronald Birthday Cake Chocolate and Ronald Birthday Cake White. So, it’s not a myth! This thing truly exists!

A few TikTok users have managed to get their hands on the sheet cake and posted on the social media app, showing what the cake looks like and describing how the dessert tastes.

“This is your sign to get a sheet cake from McDonald’s to surprise your friend,” one TikTok video says in text-overlay. The video, posted by a user named Ellie, films herself in her car, going through the drive-thru to order the cake.

“Do you have any sheet cakes?” she asks the McDonald’s employee working the drive-thru.

“Um, we should! Let me double check,” the employee responds.

After confirming they do, in fact, have some sheet cakes (in chocolate and white cake), the worker says, “Let me remember where they are. They’re so good.”

However, after receiving the cake and trying a bite, Ellie had a different opinion on the flavor.

“I give it a solid 6/10 for flavor and 10000000/10 for decoration,” she captioned the video.

The video racked up a few hundred thousand views with thousands of users chiming in that this sheet cake secret was blowing their minds.

“McDonald’s has cake?? I feel like I’m in a parallel timeline or something 😂,” one user wrote.

Another echoed, “I was today years old when I learned McDonald’s has sheet cakes.”

One user noted, “These are available wherever there’s a PLAY PLACE. I buy these as well as bags of ice. McDonalds is for way more than Burgers, Fries, and Nugs.”

(And yes, you can buy bags of ice at some McDonald’s restaurants!)

The OP responded, “The McDonald’s I went to didn’t have a play place so maybe they are expanding to more stores??”

One user questioned how good these cakes would taste and wrote, “I just feel like their cakes gotta taste like the inside of a refrigerator or freezer burn.”

The OP said, “Surprisingly, I didn’t taste freezer, but it was definitely not high on my ratings of cakes.”

One user noted that the McDonald’s mascot of Ronald McDonald was discontinued several years ago, which could mean bad news for how long that cake’s been in the freezer.

“Ronald was discontinued in 2016, so that cake has been in their freezer at least 7 years,” the TikTok user said.

Other users reminisced about how these McDonald’s sheet cakes reminded them of the legendary McDonald’s birthday parties that 80s and 90s kids used to have.

“Man, I had my 6th or 7th birthday party at McDonald’s. Sad they don’t have those crunchy decoration pieces still 😂” one user joked.

“Are these just left over from the 80s when we had them at our birthday parties? 😂”

TODAY spoke to a McDonald’s rep in 2021 and reported that “all McDonald’s owners/operators across the country have the option of ordering the cakes … from their local distribution center.”

“Occasionally, restaurants decide to let customers purchase the cakes, but they’re not on the official menu and you won’t find them at all locations.”