In a small saucepan, combine milk and lemon balm, lemon thyme, and/or lemon verbena. Bring to just boiling; remove from heat. Let stand at room temperature 20 minutes to cool.
Grease and lightly flour the bottom and 12 inch up the sides of a 9x5x3-inch loaf pan; set aside. In a medium bowl, combine the flour, baking powder and salt; set aside.
In a large mixing bowl, beat butter with an electric mixer for 30 seconds. Add sugar; beat till well combined. Add eggs, one at a time, beating after each addition. Add flour mixture and milk mixture alternately to beaten mixture, beating on low speed after each addition till just combined. Stir in lemon peel. Pour batter into the prepared pan.
Bake in a 325 degree F oven for 50 to 55 minutes or till a wooden toothpick inserted near the center comes out clean.
Cool loaf in the pan on a wire rack for 10 minutes. Meanwhile, whisk together the powdered sugar and lemon juice. Place a sheet of waxed paper under the wire rack. Remove loaf from pan; return to wire rack. Immediately drizzle or brush the lemon-sugar mixture over the top of the hot loaf. Cool bread completely on the wire rack.
To serve, slice and arrange on a serving plate. Garnish with sprigs of lemon thyme, if you like.