Weigh out the ingredients
You'll need cake flour, sugar, butter, eggs, oil, raspberry preserves, white chocolate, whole milk, vanilla extract, baking powder, and salt.
Mix dry ingredients
In the bowl of a stand mixer fitted with the paddle attachment, combine the flour, sugar, baking powder, and salt. Cut up the butter into small cubes and add to the dry ingredients. Mix on low speed until it resembles wet sand.
Add the oil, milk, and two teaspoons vanilla and mix until just combined.
Add wet ingredients
In a separate bowl using an electric mixer, whip the egg whites to medium peaks.
Whip egg whites
Gently fold the egg whites into the cupcake batter with a rubber spatula until just combined.
Fold into batter
Fill the cupcake liners about ⅔ of the way full. Bake the cupcakes for 16-18 minutes or until a toothpick inserted comes out clean. Cool completely before decorating.
Melt white chocolate, then whip egg yolks and sugar together. Heat sugar and water, then boil. Slowly add sugar syrup to the whisking egg mixture until cooled down. Add butter, then the white chocolate and vanilla extract and mix until completely smooth.
Make the buttercream
Remove the centers of the cupcakes, pressing about ⅔ of the way into them. Cut the very top of the centers off and reserve them. Pipe the raspberry preserves into the cupcakes and place the top of the centers back on.
Fill the cupcakes
Transfer the buttercream into a piping bag with a medium star piping tip and decorate each cupcake as desired.
Frost the cupcakes