Preheat your oven to 340°F/170°C and line a cupcake pan with paper liners.
In a medium bowl, combine the cake flour, baking powder, baking soda, and salt. Set aside.
In a large bowl, cream the butter and sugar. Stir in the eggs, sour cream, oil, and black tahini. Add the flour mixture and stir until just combined. Stir in the milk.
Fill the cupcake liners slightly over halfway, about ⅔ of the way, and bake for 14-16 minutes. If you insert a toothpick and it comes out clean, they're done. Transfer them to a wire rack immediately and let them cool completely.
Frosting
In a bowl, beat the butter and black tahini. Add the powdered sugar a little at a time and continue beating. Add the heavy cream and beat until fluffy.
Put the frosting in a piping bag and frost each cupcake, and top with the white chocolate eyeballs.