Preheat your oven to 350°F (175°C).
Lightly grease the mini cupcake pan or use mini cupcake liners.
In a medium bowl, whisk together the all-purpose flour, baking powder, and salt until well combined. Set aside.
In a large mixing bowl, beat the unsalted butter and granulated sugar together until light and fluffy.
Add the egg and vanilla extract to the butter mixture and beat until thoroughly combined.
Gradually add the dry ingredients to the wet mixture, alternating with the milk. Mix until just combined.
Spoon the batter into the mini cupcake pan, filling each cavity about 2/3 full.
Bake for 10-12 minutes or until a toothpick inserted in the center comes out clean.
Remove from oven and allow to cool in the pan for 5 minutes, then transfer to a cooling rack.
In a separate bowl, beat the unsalted butter until creamy. Gradually add the powdered sugar, heavy cream, vanilla extract, and a pinch of salt. Beat until fluffy.
Once the cupcakes are cool, use a piping bag to frost them with the creamy frosting.
