Step 1

Preheat oven to 350 degrees. In a large, heat proof mixing bowl, whisk together granulated sugar and brown sugar (lumps are fine), then whisk in cocoa powder, baking soda and salt. Carefully pour boiling water in to cocoa mixture and immediately whisk to blend well, about 15 - 20 seconds. Allow to cool 5 minutes.

Step 2

Using an electric hand mixer set on low speed blend in canola oil until combined, about 10 seconds. Add eggs to cocoa mixture and blend on low speed just until combined, about 5 seconds.

Step 3

Add egg yolks and vanilla extract and blend just to combined. Then add flour and blend just until combined. Pour in milk and sour cream and blend 1 minute on low speed.

Step 4

Divide batter among 12 paper lined muffin cups, filling each cup about 2/3 full. Bake in preheated oven 18 - 20 minutes until toothpick inserted into center of cupcake comes out clean.

Step 5

Cool several minutes in muffin tin, then transfer to a wire rack and allow to cool completely (I transferred to an airtight container after about 25 minutes of cooling to seal in moisture).

Step 6

Once cool, pipe Vanilla Bean Buttercream Frosting over cupcakes and drizzle each with chocolate sauce and sprinkle with nuts. Add another small bit of frosting and top with a maraschino cherry.

Step 7

For the chocolate sauce:

Step 8

Place chocolate chips in a heat proof bowl. Bring cream just to a boil in a small saucepan, then carefully pour hot cream over chocolate chips. Stir until melted. Cool slightly (until it's not so runny).

Step 9

For the Vanilla Bean Buttercream Frosting:

Step 10

In the bowl of an electric stand mixer, using the paddle attachment whip butter with vanilla bean seeds on medium-high speed until nearly white and very fluffy.

Step 11

Blend in vanilla extract. Add in 1 cup of the powdered sugar, then and heavy cream and mix on low speed until combined.

Step 12

Add remaining powdered sugar and blend on low speed until combined then increase speed to medium and beat until very light and fluffy, about 5 - 6 minutes, frequently scraping down the sides and bottom of the bowl.