Preheat your oven to 350°F (175°C) and line a muffin tin with cupcake liners.
In a bowl, whisk together flour, baking powder, and salt. Set aside.
In a separate bowl, beat butter and sugar until light and fluffy.
Add eggs one at a time, beating well after each addition.
Scrape the vanilla bean seeds from the pod and mix them into the batter along with the vanilla extract.
Gradually mix in the dry ingredients, alternating with milk and sour cream, until just combined.
Fill cupcake liners ¾ full with batter.
Bake for 18–20 minutes, or until a toothpick inserted in the center comes out clean.
Let the cupcakes cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.
Beat butter until creamy and smooth.
Gradually add powdered sugar, mixing well.
Scrape the vanilla bean seeds into the frosting and add the vanilla extract.
Add heavy cream one tablespoon at a time until you reach the desired consistency.
Beat for 2–3 minutes until the frosting is light and fluffy.
Once cupcakes are fully cooled, pipe or spread the frosting on top.
Optionally, garnish with sprinkles, edible pearls, or a light dusting of vanilla sugar.