Preheat oven to 350°F .Combine all the lemon bread ingredients in a mixing bowl and mix well.Pour into a greased bread pan and bake for 35- 40 minutes (mine needed closer to 45 min)or until golden on top and middle is cooked through. (If the top starts to get too brown towards the end of the cooking time, put some foil over the top.)Make the frosting while the lemon loaf is in the oven.mix butter, powdered sugar, and vanilla. Add hot water 1 tablespoon at a time until the glaze reaches desired consistency.Take loaf out of oven and let sit just for 5-7 minutes. The loaf needs to be warm for the frosting for melt all over it and form a coating.Place warm loaf on a rack with a baking sheet underneath to catch the frosting drippings.Spread frosting all over the top of the loaf and let the heat from the loaf naturally slowly melt it over the sides.When it looks how you like, put the entire loaf in the freezer for 5 minutes to stop the frosting from melting and it will firm up. Then put the loaf in the refrigerator so everything will thicken up nice and firm. Enjoy with a wonderful cup of hot tea!