Preheat oven to 350 degrees F. In large heat proof mixing bowl, whisk together cocoa powder and baking soda. Carefully pour in boiling water and whisk until bubbling subsides and mixture is well blended, allow to cool for 5 minutes.
Meanwhile, in a separate large mixing bowl, using an electric hand mixer set on low speed, blend together melted butter, vegetable oil, granulated sugar, vanilla and salt until well combined, about 30 seconds. Stir in egg and egg yolk. Blend in cocoa mixture then blend in heavy cream. Slowly mix in flour and blend until combined, while scraping down sides and bottom of bowl.
Spoon an even 1/8 cup (2 Tbsp) into bottom of 22 paper lined muffin cups and spread into an even layer, set aside.
For the white vanilla cupcake:
Sift cake flour into a medium mixing bowl. Add baking powder and salt and whisk mixture 20 seconds, set aside. In the bowl of an electric stand mixer fitted with the paddle attachment, whip together butter and sugar with vanilla bean seeds on medium-high speed until pale and fluffy. In separate mixing bowl whisk together milk, egg whites and vanilla extract until well blended.
Add 1/3 of the flour mixture to butter/sugar mixture, then mix until combined, then add 1/2 of the milk/egg mixture and mix on low speed until combined then increase to medium speed and mix 1 minute (if you are using a paddle attachment that doesn't constantly scrape bowl, then mix 1 1/2 minutes and occasionally scrape down sides and bottom of bowl throughout mixing.
Batter should become fluffy). Add another 1/3 of the flour mixture and mix until combined, then add remaining 1/2 of the milk/egg mixture and mix on low until combined then increase to medium and mix 1 minute (1 1/2 minutes with regular paddle attachment, it should have the consistency similar to fluffy mousse). Add last 1/3 of the flour mixture and mix until well combined.
Gently dollop a heaping 1/8 cup over chocolate layer in cupcake wells and carefully spread batter evenly to edges.
Bake in preheated oven until toothpick inserted into center of cupcake comes out clean, about 16 - 19 minutes. Cool in baking sheet several minutes then transfer to a wire rack to cool completely (once cool immediately store in an airtight container). Pipe or spread strawberry frosting over cupcake once cooled.