Add the powdered sugar and lemon juice to a small bowl.
Add more of the lemon zest here as well.
Add more of less of each ingredient until you get the consistency you are looking for. You want it runny, but not to runny.
Once the bread is done in the over, drizzle over the icing. Let it cool just a little. If it is too hot all the icing will run down to the bottom. You want some of it to stick on the top.