Preheat the oven to 350 degrees F. Line a 12-cup muffin tin with liners. Depending on how many muffin tins you have, you may need to work in batches. Set aside.

In a medium bowl, whisk together the cake flour, dark cocoa powder, baking powder, baking soda, and salt. Set aside.

In the bowl of a stand mixer, cream the butter and sugars together. Add the eggs, one at a time, mixing well between additions. Add the vanilla extract.

Alternate between adding some of the dry ingredients with the buttermilk. After the last addition, mix until just combined. Scrape down the sides, making sure to get the bottom, too. Turn on the stand mixer for another 30 seconds - 1 minute, just for good measure.

Fill the liners ⅔ of the way full. Bake for 20-25 minutes (make sure to start checking after 20!), or until a knife/toothpick, when inserted into the center of the cupcake, comes out clean.

Allow the cupcakes to cool for 10 minutes in the muffin tin, then remove and place them on a wire rack to finish cooling completely.

Using a stand mixer fitted with the paddle attachment, beat the butter on medium speed until it is softened (about 1 minute).

Add 2 cups of the powdered sugar and beat on low speed until well combined.

Add another 2 cups of powdered sugar along with 1 tbs of heavy cream/milk. Beat until combined.

Add the remaining 1-2 cups of sugar (depending on your desired consistency) and remaining cream/milk and beat until the frosting reaches the desired thickness.

Add the raspberry preserves and beat until thoroughly mixed through. Beat on medium speed until the frosting is smooth and fluffy (about 4 minutes).

Frost the cupcakes however you like. I'm partial to piping roses with a Wilton 1M piping tip and piping bag.