• Preheat oven to 325°F. Generously grease a 10 to 12-cup Bundt pan with butter and flour or nonstick baking spray.
• In a large bowl of a stand mixer fitted with the paddle attachment, beat the cream cheese and butter until completely smooth and creamy, about 3 minutes.
• Gradually add the sugar and mix until light and fluffy, scraping down the bowl as needed.
• Add the eggs one at a time, mixing well after each addition. Mix in the vanilla extract until combined.
• On low speed, gradually add the cake flour and mix just until incorporated.
• Remove the bowl from the mixer. Add the buttermilk and stir gently by hand with a rubber spatula until just combined, scraping the sides and bottom of the bowl.
• Fold in the rainbow sprinkles until evenly distributed. Do not overmix to help prevent color bleeding.
• Pour the batter into the prepared bundt pan and smooth the top. Bake for 1 hour to 1 hour 20 minutes, checking at the 1-hour mark. The cake is done when a toothpick inserted into the center comes out with a few moist crumbs, but no wet batter.
• Let the cake cool in the pan for 5 minutes, then carefully turn it out onto a wire rack to cool completely.

Glaze

• In a medium bowl, combine the confectioners’ sugar and milk. Whisk until you achieve a smooth and pourable glaze. Add more milk if necessary to reach the desired consistency.
• After the cake has cooled completely, pour the glaze over the top of the pound cake, allowing it to drizzle down the sides. Immediately sprinkle additional rainbow sprinkles over the glaze, if desired.