Preheat oven to 350º.
Grease a loaf pan and set aside.
In a medium bowl, whisk together flour, baking powder, and salt.
In another bowl, whisk together the milk and the zest of one lemon.
With an electric mixer, cream butter and sugar on high until light and fluffy.
Turn the mixer down to medium-low.
Add eggs one at a time.
Add the flour mixture, then the milk mixture, alternating a few times, ultimately ending with the milk mixture.
(flour, milk, flour, milk, flour, milk)
Add batter to greased pan, and bake for 45 minutes.
In the last 10 minutes of baking, make the simple syrup glaze:
In a small saucepan, add the juice of the lemon and 1/2 cup sugar.
Let it cook on low, stirring often, until the mixture is clear.
Never let it boil.
When the cake has just come out of the oven, pour the glaze over it and let it soak in.
Let the cake cool in the pan.