1. In a bowl, sift together the flour, baking soda, baking powder, and kosher salt and set aside.
2. Beat the butter and sugar in a separate clean, large bowl with an electric beater on high until fluffy.
3. Add the eggs in, one at a time, beating after each addition. Add in the vanilla extract.
4. Add the sour cream, then turn beater to low (or switch to a whisk) and gently stir in the flour mixture.
5. Stir in the white chocolate chips at the end.
6. Pour into a cupcake pan with liners, distributing evenly among 12.
7. Bake at 350 degrees F for about 15 minutes or until a toothpick inserted comes out dry.

For the filling

1. Puree all the ingredients in a blender or processor or bullet.
2. Push the finished sauce through a sieve to remove any raspberry seeds.
3. Use a knife or a cupcake corer to cut out a hole in the center of each cooled cupcake.
4. Add a spoonful or so of the raspberry puree (I like to make a fairly large hole and fill it up to the top).
5. Top with part of the cake that you just removed so that the puree is buried in the center.

For the Frosting

1. Beat all the frosting ingredients together with an electric beater on high until fluffy.
2. Add more milk to make it creamier, or more sugar to make it stiffer.
3. Swirl frosting on top with a spoon or piping bag with a star tip.
4. *For the rose effect, I used a star tip and started swirling from the inside out.