Preheat the oven to 350F degrees. Butter & flour a 9x5 inch loaf pan, or line the loaf pan with parchment paper.
In a medium bowl whisk together the flour, baking powder & salt.
In a large bowl beat together the butter, sugar and lemon zest until fluffy.
Beat in the eggs and vanilla extract, then stir in the lemon juice.
With the mixer on low, mix in about 1/2 of the dry ingredients, followed by about 1/2 of the sour cream. Repeat with the rest of the dry ingredients and sour cream.
Pour the batter into the prepared loaf pan and bake for 45-55 minutes until an inserted toothpick comes out clean or with a few crumbs.*
Remove from the oven and let cool at room temperature.
Once cooled, whisk together the lemon juice and icing sugar for the glaze. Adding a little more lemon juice or powdered sugar as necessary.
Remove the lemon loaf from the pan and pour or drizzle the glaze over top.