• Preheat the oven to 350°F.
  
• In another medium bowl, mix together flour, baking powder, and salt.
  
• In a large bowl, beat the butter and sugar together until light and pale with a mixer.
  
• Whisk together the eggs in a separate bowl. Add in the vanilla.
  
• Add sour cream and mix well.
• Add egg mixture ½ at the time into a bowl with butter and sugar.
  
• Add dry ingredients ⅓ at the time into a bowl with wet ingredients, mixing between each addition.
  
• Gently fold rainbow sprinkles in with a spatula.
  

Bundt cake pan coating

• Grease bundt cake with vegetable shortening.
  
• Sprinkle pan over with flour—roll flour inside the bundt cake. Don't shake off access flour.
• Pour cake batter into bundt pan evenly.
  
• Bake for 50-65 minutes, or a toothpick inserted in the center comes out clean.
• Cool for 10 minutes before removing from the pan.
  
• Remove cake from the pan into the wire rack. Cover with a kitchen towel and let cool for 30-40 minutes.
  
• Flip cake upside down into the cutting board. Cut 6 holes with an apple corer.
  

Garnish

• Put store-bought buttercream frosting into a large mixing bowl and mix on medium speed with a hand mixer, 2-3 minutes.
  
• With a toothpick, add pink food coloring. Mix until color is combined.
  
• Transfer 1/3 of buttercream frosting into a piping bag and close with a piping bag tie.
  
• Cut with scissors 1/2 inch from the tip of the piping bag. Pipe buttercream frosting into the holes and close them with cake.
  
• Carefully flip bundt cake into the cake stand or serving plate.
  
• Spoon the rest of the buttercream frosting on top. Sprinkle with confetti rainbow sprinkles.