Preheat oven to 350°. Grease and flour two 5-3/4x3x2-in loaf pans., In a large bowl, cream butter and sugar until light and fluffy. Add 1 egg at a time, beating well after each addition. Beat in lemon zest and extracts. In another bowl, whisk flour, salt and baking soda; add to creamed mixture alternately with sour cream, beating well after each addition., Transfer to prepared pans. Bake 35-40 minutes or until a toothpick inserted in center comes out clean. Cool in pans 10 minutes before removing to wire racks to cool completely., In a small bowl, mix icing ingredients. Spoon over loaves. Freeze option: Do not make icing. Securely wrap cooled loaves in plastic wrap and foil, then freeze. To use, thaw at room temperature. Prepare icing as directed.