Preheat the oven to 425°. In a large bowl, mix the flour, sugar, lemongrass, baking powder, pepper and salt. Using 2 knives or a pastry blender, cut in the butter until it is the size of small peas. In a small bowl, whisk the milk with the egg. Make a well in the center of the dry ingredients and add all but 1 tablespoon of the milk mixture; stir until the dough is evenly moistened. Gather the dough into a ball and knead a few times, just until it comes together.