01 - Preheat oven to 350°F. Grease and line a 9x5-inch loaf pan with parchment paper.
02 - Whisk together flour, baking powder, baking soda, and salt in a medium bowl.
03 - Using an electric mixer or whisk, beat butter and sugar until light and fluffy, about 2 to 3 minutes.
04 - Beat in eggs one at a time, mixing thoroughly after each addition.
05 - Mix in lemon zest, fresh lemon juice, and vanilla extract until combined.
06 - Alternately add the dry ingredient mixture and milk to the butter mixture, beginning and ending with dry ingredients; mix until just combined without overmixing.
07 - Pour batter into loaf pan and level the surface.
08 - Bake for 45 to 50 minutes or until a toothpick inserted into the center comes out clean.
09 - Allow loaf to cool in the pan for 10 minutes, then remove and transfer to a wire rack until completely cool.
10 - Whisk powdered sugar with enough lemon juice to create a thick but pourable glaze.
11 - Drizzle lemon icing over the cooled loaf and allow it to set before slicing.