Preheat oven on low broil. Have the rack about 8 inches from the broiling element. Slice the sourdough bread on the diagonal, about 1/2 inch thick slices. Lightly spread the pieces with the butter, then add the pistachios and the parmesan cheese, sprinkling evenly. Place under broiler and cook for 2 minutes, keeping a careful eye. When cheese just starts to melt and bread just starts to lightly tan, remove and crack the fresh pepper on top, then drizzle with the olive oil and serve.