Preheat oven to 180 degrees C. Lightly grease 2 loaf tins.
Sift together the flour, baking powder, ginger and salt in a bowl; set aside. Cream together the butter and sugar in a separate large bowl; beat in the eggs. Stir in the lemon zest and orange liqueur. Add the buttermilk. Add the flour mixture while whisking gently. Pour the mixture into the prepared loaf tins.
Bake in the preheated ovens until a skewer inserted in the centre comes out clean, about 50 minutes. Remove from pans and move to a cooling rack.
Whisk together the lemon juice and sugar until the sugar dissolves. Gently drizzle the mixture over the hot loaves. Allow the loaves to cool completely before serving.