Preheat oven to 350℉/177℃.
Line muffin pans with paper liners, or spray with baking spray.
Combine chocolate and butter in a microwave-safe bowl.
Heat in 15 second increments, stirring after each, until melted and smooth. Set aside.
In a large bowl, whisk together flour, salt, baking powder, baking soda, and sugar.
Add eggs and buttermilk.
Whisk until combined.
Stir in chocolate mixture and vanilla.
Use a 3 Tablespoon scoop to portion batter in prepared pans.
Bake for 15 minutes, or until cupcakes test done.