Place the rack in the top third of the oven and preheat to 375°F.
Combine the Pamela's Biscuit & Scone Mix, butter, a pinch of salt and a pinch of pepper in the bowl of a food processor fitted with the "S" blade. Pulse until the butter into the dry mix until pea-sized crumbs are formed.
Transfer to a mixing bowl and add the 1¼ cups of buttermilk, stir to incorporate. If the mixture still seems a bit dry add a teaspoon of the additional buttermilk at a time, stirring and folding after each addition until all of the dry mix is incorporated. Add the cheese, peppers or tomatoes, and rosemary. Fold until just incorporated.
On a parchment covered sheet pan, form the dough into a 1" to 1½" high round and cut into wedges. Brush the remaining buttermilk over the top. Bake for 25- 28 minutes until golden. Remove the pan to a wire rack to cool.