• Preheat your oven to 325 degrees F. Spray three 8-inch cake pans with cooking spray and line them with parchment paper. Spray again. Set aside.
• In a stand mixer fitted with the paddle attachment, combine flour, sugar, cocoa powder, baking soda, baking powder, and salt. Mix on low until evenly combined.
• In a small bowl, whisk together eggs, buttermilk, hot water, vanilla extract, and vegetable oil until evenly combined.
• With the mixer on the lowest speed, pour the liquid ingredients into the dry ingredients and mix just until combined. Scrape the bottom of the bowl with a rubber spatula to ensure even mixing.
• Divide the batter evenly between the prepared pans and bake for 30-33 minutes. To check to see if the cake are done, insert a toothpick and it is done when the toothpick comes out or a few crumbs. You want to aim for a few crumbs. Allow the cakes to cool in the pans for 15 minutes, then transfer them to a cooling rack to cool completely.
• Once the cakes are at room temperature, level the tops if needed, wrap them in plastic wrap, and freeze in preparation for frosting.

For the cream cheese buttercream

• In the bowl of an electric mixer, combine the butter and cream cheese. Beat on medium speed for about 2 minutes. Scrape down the sides and bottom of the bowl. Beat again for 2 more minutes.
• With the mixer on low, add the powdered sugar, followed by the cream, vanilla extract, vanilla bean paste, and a pinch of salt. Beat on low just until combined. With a rubber spatula, scrape down the sides of the bowl.
• Turn the mixer up to medium speed and beat for about 3 to 5 minutes.
• With a rubber spatula or a wooden spoon, beat out all of the air pockets by hand for a smooth look.

Assembly

• Place the first cake layer, top side up. Add about 1 cup of frosting. With an off set spatula, spread over the cake layer as evenly as possible to the edges of the cake. Get eye level to make sure the frosting is even.
• Repeat this step until you get to the final cake layer, which you will lay top side down.
• Apply a thin coat of buttercream around the entire cake to lock in the crumbs. Freeze for about 10 minutes.
• After the crumb coat is set, apply the rest of the frosting, and garnish with rainbow sprinkles.
• This cake is served best at room temperature. Wrap the cake in plastic wrap and it can be stored in the fridge for up to 5 days. You can also wrap each individual slice in plastic wrap and store in the freezer for up to 30 days.