Preheat your oven to 350°F (175°C). This ensures that your cupcakes will bake evenly.
Line a muffin tin with cupcake liners, or grease it lightly to prevent sticking.
In a medium bowl, whisk together the flour, baking soda, and salt. Set this mixture aside for later.
In a large mixing bowl, use an electric mixer to cream the softened butter and packed brown sugar until the mixture is light and fluffy, about 2-3 minutes.
Beat in the large egg and vanilla extract into the creamed butter and sugar, mixing until well combined.
Gradually add the dry ingredients into the wet mixture, stirring gently until just combined.
Using a rubber spatula, gently fold in the quick-cooking oats and 6 ounces of chopped dark chocolate until well distributed throughout the batter.
Scoop the batter into the prepared muffin tin, filling each liner about three-quarters full.
Bake in the preheated oven for 18-20 minutes or until a toothpick inserted into the center comes out clean.
Once baked, remove the cupcakes from the oven and allow them to cool in the pan for about 5 minutes before transferring to a cooling rack. While cooling, melt the remaining 2 ounces of dark chocolate with 1 tablespoon of cream in a microwave-safe bowl, stirring every 30 seconds until smooth. Drizzle this melted chocolate over the cooled cupcakes for a decadent finish.
