-
1
Heat the oven to 350 degrees F and arrange a rack in the middle.
-
2
Using 2 (12-well) muffin pans, line 18 of the wells with paper liners (leave the remaining 6 empty); set aside.
-
3
Place the cream cheese and sugar in the bowl of a stand mixer fitted with the paddle attachment and beat on medium speed until smooth, about 1 to 2 minutes.
-
4
Stop the mixer and scrape down the sides of the bowl and paddle with a rubber spatula.
-
5
Add the egg, return the mixer to medium speed, and beat until incorporated, about 1 minute.
-
6
Stop the mixer and scrape down the sides of the bowl and paddle with the rubber spatula.
-
7
Turn the mixer to low speed, add the chocolate, and mix until just combined, about 20 seconds.
-
8
Transfer the cream cheese mixture to a medium bowl.
-
9
Wash and dry the mixer bowl and paddle attachment and return them to the stand mixer.
-
10
Place the flour, cocoa powder, baking soda, and salt in a medium bowl and whisk to aerate and break up any lumps; set aside.
-
11
Mix together the buttermilk and vanilla in a small bowl or measuring cup and set aside.
-
12
Place the sugar and oil in the mixer bowl and mix on medium speed until combined, about 1 minute.
-
13
Reduce the speed to low and slowly add half of the flour mixture, mixing until just combined.
-
14
Add half of the buttermilk mixture and mix until just combined.
-
15
Repeat with the remaining flour and buttermilk mixtures, mixing until combined, about 2 minutes total.
-
16
Fill the prepared muffin wells about halfway with the cupcake batter.
-
17
Divide the cream cheese topping among the cupcakes (about a heaping tablespoon for each).
-
18
Place the muffin pans side by side in the oven and bake for 10 minutes.
-
19
Rotate the pans front to back and side to side and bake until a toothpick inserted into the center of the cupcakes comes out clean, about 8 to 10 minutes more.
-
20
Place the pans on wire racks and let them cool for 15 minutes.
-
21
Remove the cupcakes from the pans and cool completely on the racks before serving.
