Though many in the Kardashian-Jenner clan posted pics at the time of the event, on Tuesday, Kim, 37, shared even more details on her official app.
"North and Penelope have been really into unicorns, so when we threw them their joint birthday party, we knew that had to be the theme!" Kim writes on her app. "We had ponies with unicorn horns, a cotton candy and s’mores station, a 'unicorn snot' glitter slime craft station and music by DJ Livia - she’s only 10 years old and she was so good!"
North and Penelope also chowed down on identical unicorn candy-filled birthday cakes at their party as they looked adorable in their matching rainbow bathing suits!
Kim shared pics of the girls blowing out candles, getting cotton candy and making crafts.
The new details of the bash come after Kim and Kourtney brought their broods to New York City over the weekend, largely in support of 41-year-old Kanye, who served as the musical guest on Saturday Night Live.
A source told ET that Kim and Kourtney, along with their children, were all present during Kanye's speech. The source also noted that Kim just stared at Kanye -- who recently announced that he's changing his name to Ye -- and didn’t seem fazed by his remarks, despite him receiving audible boos from the crowd.