Preheat your oven to 350°F (175°C).
Line a cupcake tin with paper liners.
In a mixing bowl, cream the butter and sugar together until light and fluffy.
Add the eggs one at a time, mixing well after each addition.
Mix in the vanilla extract and buttermilk until combined.
In a separate bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, mixing until just combined.
Fold in the rainbow sprinkles gently.
Spoon the batter into the lined cupcake tins, filling them about 2/3 full.
Bake for 15-18 minutes or until a toothpick comes out clean.
Let the cupcakes cool in the pan for about 5 minutes before transferring to a wire rack.
