For the Chocolate Cupcakes:

1. Preheat oven to 350°F (175°C).

2. Cream together granulated sugar and softened butter until light and fluffy.

3. Add 1 egg, 1 egg yolk, and vanilla extract. Mix until combined.

4. Stir in buttermilk until well blended.

5. In a separate bowl, sift together all-purpose flour, cocoa powder, baking powder, baking soda, and salt.

6. Gradually add the dry ingredients to the wet ingredients and mix until smooth.

7. Stir in hot brewed coffee for extra moisture.

8. Line a cupcake pan with 14 cupcake liners and fill each liner 3/4 full with batter.

9. Bake for 20-22 minutes, or until a toothpick comes out clean.

10. Let cupcakes cool for 5 minutes in the pan, then transfer to a wire rack to cool completely.

For the Edible Cookie Dough:

1. Preheat your oven to 350°F (175°C). Spread the flour on a baking sheet and bake for 5 minutes to heat treat it. Allow to cool.

2. Cream together softened butter, granulated sugar, brown sugar, and vanilla until smooth.

3. Add the cooled flour and salt, mixing until fully combined.

4. Gradually add 3-4 tbsp of milk, mixing until the dough reaches a cookie dough consistency.

5. Stir in mini chocolate chips.

For the Vanilla Buttercream:

1. Beat softened butter with an electric mixer until pale and fluffy.

2. Add vanilla and salt, then gradually add powdered sugar, mixing until light and fluffy.

Assembling the Cupcakes:

1. Once the cupcakes are completely cool, use a spoon or knife to hollow out the center of each cupcake.

2. Fill each cupcake with edible cookie dough.

3. Transfer vanilla buttercream into a piping bag with a decorative tip and pipe a generous swirl on top of each cupcake.

4. Optionally, sprinkle mini chocolate chips on top of the frosting for extra flair.