Preheat your oven to 350°F (175°C) and line a cupcake tray with graduation-themed cupcake liners.

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

In a large mixing bowl, cream the softened butter and sugar together until light and fluffy, about 2-3 minutes.

Beat in the eggs one at a time, followed by the vanilla extract.

Gradually add the dry ingredients, alternating with the milk and sour cream, starting and ending with the dry ingredients. Mix until just combined.

Divide the batter evenly among the cupcake liners, filling each about 2/3 full.

Bake in the preheated oven for 18-22 minutes, or until a toothpick inserted into the center comes out clean.

Let the cupcakes cool in the tray for 5 minutes, then transfer them to a wire rack to cool completely.

To make the frosting: In a large bowl, beat the softened butter until creamy. Gradually add the powdered sugar, one cup at a time, mixing on low speed. Add the vanilla extract and heavy cream, and beat on high speed for 3-5 minutes until fluffy.

Once the cupcakes are completely cool, frost them using a piping bag or spatula.

Decorate with graduation-themed sprinkles or decorations, and top with edible graduation caps for an extra celebratory touch.