You start with the chocolate cupcake base. You can use your favorite from scratch recipe or box mix. I use the Hershey's "Perfectly Chocolate" Chocolate cake recipe:
Once your cupcakes are cooled, top with a chocolate buttercream icing. Garnish as desired. To drizzle with fudge, I microwave a jar of hot fudge sauce for 30 seconds. Long enough to make it gooey but not long enough to make it hot. Put the fudge in a ziploc bag or decorator bag (disposable or fitted with a #2 tip). Snip the corner and start drizzling.