In a large bowl, combine flour, baking powder, salt and sugar.
Add the butter to the flour mixture and rub it in with your fingertips, working until mixture is sandy and the butter seems fairly evenly distributed, with a few larger bits, but none larger than a pea.
Stir in 1/2 cup buttermilk (reserving the rest), the apple and the granola. Add the remaining buttermilk 1 tbsp at a time until the dough comes together into a ball. It should not be too sticky, nor should it be floury. Add back an additional tablespoon of flour if your dough becomes too wet.
Divide ball into two equal discs about 1-inch thick and cut each disc into quarters. Place triangular scones on a parchment-lined baking sheet and sprinkle with brown sugar.
Bake for about 20 minutes at 400F until light golden brown. The bottoms should be browned.
Cool on a wire rack for at least 5-10 minutes before serving. Scones can be eaten warm or at room temperature.