Preheat the oven to 180°C (350°F).

Grease a rectangular baking tin with butter and dust it with flour to prevent the cake from sticking.

In a large mixing bowl, cream together the butter and castor sugar using an electric beater until light and fluffy.

Add the eggs one at a time, beating well after each addition until fully combined.

Sift the flour and baking powder together, then gradually fold this mixture into the butter-egg mixture until well incorporated.

Mix in the blue food color until the batter is evenly colored.

Add the buttermilk and gently mix until the batter is smooth and uniform.

Pour the prepared batter into the greased and dusted baking tin, filling it about ¾ of the way.

Place the tin in the preheated oven and bake for 35-40 minutes, or until a toothpick inserted in the center comes out clean.

Remove from the oven and let it cool in the tin for a few minutes before demolding.

Once cooled, carefully remove the crust of the cake using a serrated knife and cut the cake into small squares.

Arrange the squares on a serving plate, and pipe a generous dollop of cream cheese onto each one.

Sprinkle colorful edible sprinkles over the top for added decoration and fun!

Serve immediately to enjoy these delicious bites at their freshest!