For the Chocolate Cupcakes:
Preheat the oven to 350°F (175°C). Line 2 muffin tins with cupcake liners and set aside.
In a large bowl, whisk together the flour, cocoa powder, baking powder, and salt. Set aside.
Using a stand mixer or hand mixer, whip together the sugar, vegetable oil, and egg on low speed for 1 minute.
Add the milk and vanilla extract, mixing until combined, about 1 minute.
Slowly add the dry ingredients to the wet ingredients, about 1/2 cup at a time, mixing on low speed. Mix just until the dry ingredients are no longer visible, being careful not to overmix.
Pour the batter into the prepared muffin tins, filling each liner about halfway.
Bake the cupcakes for 20-25 minutes, or until a toothpick inserted into the center comes out clean.
Let the cupcakes cool in the tin for 5 minutes, then transfer to a wire cooling rack to cool completely.
For the Vanilla Buttercream Frosting:
Using a stand mixer or hand mixer, whip the softened butter and vanilla extract on high speed until pale and fluffy, about 5-7 minutes.
Reduce the mixer speed to medium and gradually add the powdered sugar, about 1/2 cup at a time, mixing thoroughly between each addition. If the frosting becomes too dry, add 1 tablespoon of heavy whipping cream.
Scoop out about 1/4 to 1/3 cup of frosting into a separate small bowl. Color the larger portion of frosting green and the smaller portion orange using gel food coloring. Mix until the desired color is reached.
Transfer each frosting color into its own pastry bag. For the green frosting, use a decorating tip of your choice to create the look of hair. For the orange frosting, simply cut a small hole in the corner of the pastry bag.
Putting it all together:
Decorate the top of each cooled chocolate cupcake with the green frosting to create the “hair” of the witch.
Place an Oreo Thin gently on top of the green frosting, ensuring it’s centered.
Add a small dollop (about 1 teaspoon) of orange frosting on top of the Oreo.
Press an unwrapped Hershey’s Kiss into the orange frosting, applying even pressure so that a ring of orange frosting appears around the base of the Kiss, creating the top of the witch’s hat.
Serve as desired and enjoy your spooky treats!