Preheat your oven to 350°F (175°C). Grease and flour a bundt cake pan to prevent sticking.

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

In a large mixing bowl, combine the granulated sugar and vegetable oil. Mix well until smooth and combined.

Add the Greek yogurt to the sugar mixture and mix until incorporated. Then, add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

Gradually add the dry ingredients to the wet ingredients, alternating with the milk. Begin and end with the dry ingredients. Mix until just combined, being careful not to overmix.

Gently fold in the rainbow sprinkles, ensuring they are evenly distributed throughout the batter.

Pour the batter into the prepared bundt cake pan, spreading it evenly. Tap the pan lightly on the counter to remove any air bubbles.

Bake for 45-50 minutes or until a toothpick inserted into the center of the cake comes out clean. Allow the cake to cool in the pan for about 10 minutes, then transfer it to a wire rack to cool completely.

While the cake is cooling, prepare the cream cheese frosting. In a mixing bowl, beat the softened cream cheese until smooth. Add the powdered sugar and vanilla extract, and continue beating until well combined.

Gradually add the milk, one tablespoon at a time, until the frosting reaches your desired consistency. Be careful not to add too much milk, as it may make the frosting too runny.

Once the cake has completely cooled, spread the cream cheese frosting over the top of the bundt cake using a spatula or knife.

Sprinkle additional rainbow sprinkles over the frosting for a festive touch.

Slice, serve, and enjoy your delicious homemade Funfetti Birthday Bundt Cake!