Preheat your oven to 400F (200C). Line a 6-cup muffin tin with paper liners, or butter & flour the bottom and sides.
Add the flour, sugar, salt, and baking powder to a clean deep bowl. In a small bowl or large measuring cup, combine the buttermilk, egg, and melted butter. Beat with a fork.
Pour the buttermilk mixture over the flour mixture. Stir with a fork until just combined. Using a rubber spatula, fold in the chocolate chips.
Evenly spoon into the prepared muffin tin.
Bake until a deep golden brown, about 25 minutes. Remove from the oven. Set the tray on a wire rack, and allow muffins to cool at least 10 minutes before serving.
MAKE AHEAD: Once baked, let muffins cool completely. Wrap them individually in plastic film, and store in a tightly sealed ziptop bag. Take muffins out the night before you plan to eat them, and let them thaw in the fridge overnight.