The beauty mogul just turned 24, so she hosted an at-home celebration at her Hollywood mansion with her family and close friends that kicked off with a breathtaking breakfast buffet featuring all of the favorites ... and then some.

From there, her guests -- who included Kim, Khloe, Kendall, and Kris along with her friends Anastasia Karanikolaou, Victoria Villarroel and more -- took a painting class with artist Timree Gold ... to really liven up the place and accentuate all the bouquets of flowers Kylie received.

Of course, this wasn't just a daytime shindig ... so the festivities continued with a fancy candlelit dinner with cocktails and sushi galore. It's good to be 24.

There were several fellas at Kylie's bday party too -- her brother Rob, Travis Barker, Carter Gregory and reportedly Travis Scott showed up as well.

A fun time was had by all. Happy belated, Kylie!