Step 1

For Cake: Preheat oven to 350 degrees F. Line two cupcake pans with liners.In a large bowl, sift together flour, baking powder and salt. Set aside.In a medium bowl, whisk together milk and egg whites. Set aside.In the bowl of a stand mixer fitted with the paddle attachment, beat the butter, sugar and vanilla bean seeds at medium-high until lightened in color and fluffy, about 3-4 minutes.

Step 2

Add vanilla and mix until combined. Reduce mixer speed to low and add the dry ingredients in three batches, alternating with the wet ingredients in two batches and mixing just until incorporated.Scrape down the bowl, then increase mixer speed to medium and beat for 2 minutes to ensure proper aeration.Fill the cupcake liners about 2/3 full.

Step 3

Bake for 16-18 minutes, or until a toothpick inserted in center comes out clean.

Step 4

Let cupcakes cool in pan for 5 minutes then transfer to a wire rack to cool completely.Frost with vanilla bean buttercream (recipe below) and decorate as desired.For Buttercream: In the bowl of a stand mixer fitted with the paddle attachment, cream butter, sugar and vanilla beans on medium-high until fluffy, about 4-5 minutes.Reduce mixer speed to low and gradually add the powdered sugar.

Step 5

Add in vanilla and 3 tablespoons of heavy cream or milk, blending until moistened. Increase mixer speed to medium-high and beat frosting for 2-3 minutes until smooth and fluffy.If the frosting is too thick, add additional heavy cream or milk 1 teaspoon at a time until desired consistency is reached. If the frosting is to thin, add powdered sugar 1/4 cup at a time until it thickens.Frost cupcakes as desired.