I went to South Korea and ate 17 fast-food menu items you can't order in America, from Starbucks' cheese mocha to KFC's Double Down

The worst thing I ate at McDonald's in South Korea was the McChicken Mozzarella. The McChicken, plus two mozzarella sticks, plus spicy Arrabbiata sauce was undone by the sauce, which was gross and ruined any other flavors that could be found in the sandwich. The mozz sticks quickly turned rubbery, with their outer fried layer growing soggy and almost moldy in texture.

Read more: I tried McDonald's fried chicken and mozzarella stick sandwich that is only available in Korea, and it crushed my fried cheese dreams

KFC was my favorite fast-food chain that I visited in South Korea. And, the Double Down was a definitive standout on the menu — two pieces of fried chicken, sandwiching together a hash brown, cheese, and bacon.

The hash brown elevates the massive mount of deep-fried decadence. Hopefully if this menu item ever returns to American menus, the hash brown will provide the necessary carby counterbalance to the fried chicken.

KFC also sells beer in South Korea. The brew is served in a paper cup and only costs 3,000 won, or about $2.50.

"Many KFC markets around the world offer beer to pair with the Colonel's finger lickin' good fried chicken, including in Asia at select restaurants in Japan, Korea, and Hong Kong," a KFC representative told me in an email.

"You can also find beer served in some of our markets across Europe, Russia and CIS," the email continued. "Local regulations play a large role in determining whether or not beer is included on the menu in a market."

This super-sized cheese stick popped up at a couple of chains I visited in South Korea. KFC's showcased impressive stretchiness, delicious cheese, and an expertly fried outer layer.

I was on quest to chew my way through all the delightfully chewy food Korea had to offer. KFC served up some very nice gummy rice rolls, along with some solid chicken tenders.

Whether you like these or not is probably going to come down to if you like chicken gizzards and other somewhat gristly parts of the chicken. I thought they were tasty, especially hot, and fresh out of the fryer.

The base of the sandwich was pretty similar to its solid US counterpart, but the balls of fried cream cheese kept rolling everywhere.

Still, who am I to argue with fried cream cheese? The balls added a mellow, sweet flavor to the sandwich, taking it closer to the sweet-and-salty category dominated by dishes like chicken-and-waffles.

The dish is basically a pastry topped with a dollop of mashed potato and a dollop of gravy. The potato is whipped and strangely sweet — I think it might have cream cheese in it? — and the gravy doesn't have much flavor. I don't know if I can recommend this one, but I ate the entire thing.

Read more: I've been in Korea for 10 days and have already been to KFC 3 times. Here's what makes it so special here compared to the US.

Taco Bell's menu in South Korea is very similar to its American menu, with the exception of squash soup. The sweet dish was definitely thick and flavorful. But, it was just a bit too vegetal for me, as someone who went in for a sip expecting more of a pumpkin spice flavor.

I'm counting Starbucks among fast-food chains for this list, since it is one of the largest American chains in South Korea. The Happy Cheese White Mocha was a limited-time offering, which rolled out to celebrate the "Year of the White Mouse" during the Lunar New Year, takes a sweet mocha and covers it with cheese whipped cream and a little faux Swiss cheese topper.

While I wasn't sure about mixing cheese and Starbucks, the Happy Cheese White Mocha ended up being lovely. It tasted like a white chocolate mocha, with a sweet-and-salty twist from the whipped cream. If anything, the cheese improved on the classic.

The sweet treat was part of a collaboration between Starbucks and K-pop stars BTS. Since purple is the color of the BTS fandom, the entire menu is supposed to be purple — but the cupcake ended up being more of a mauve. Also, digging in revealed that the treat was not so much a cupcake as a sort of mousse.

I preferred this BTS-branded dessert. The purple was actually purple and the flavor was rich without entering full decadent mode.

This was yet another Instagram-ready menu item from Starbucks' BTS collaboration. The drink was apparently flavored with elderflower, grape juice, and fruit, but it basically tasted like sweet iced tea with tinges of grape and florals. Still, it didn't cross the line to sickly sweetness that many Frappuccinos trample.

Read more: We visited Starbucks in Korea, where the coffee giant sells cheese-flavored mochas and purple K-pop cheesecake

Back on the subject of McDonald's — the fast-food giant serves curly fries in South Korea.

I'd put these guys up there with Arby's curly fries, which are basically a league of their own. These fries didn't have much of a flavor punch and, like traditional McDonald's fries, they quickly decline in quality as they cool. But, I would love to see them on the American menu.

I doubt we'll see this one on the American menu any time soon. But, I found the sweet chowder to be surprisingly comforting.

The Green Grape Chiller was very, very sweet, but I could not stop drinking it. It's a classic frozen drink — and one that made me wonder why green grape is such an underutilized flavor in the US.