Preheat your oven to 300°F (150°C) and grease a 9x5-inch loaf pan, or line it with parchment and set it aside.
Grate 3 lemons in a zester, then juice them in a hand juicer.
For the batter: In a large mixing bowl, combine the lemon zest and granulated sugar, then add the softened butter and mix together until creamy.
Add the eggs one at a time, mixing well after each addition.
Add the sour cream and mix, then pour in the lemon juice and stir until well combined.
In a separate bowl, whisk together the sifter flour, baking powder, baking soda, and salt.
Gradually add the dry ingredients to the lemon loaf batter, stirring until just combined.
Pour the batter into the prepared loaf pan.
Bake the bread at 300°F (150°C) for 45-55 minutes or until a toothpick inserted in the center comes out clean.
Allow the bread to cool in the pan for 15 minutes, then transfer the bread to a wire rack to cool completely.
For the glaze (optional): Grate 1 lemon in a zester, then juice it in a juicer.
Whisk together powdered sugar, lemon zest and fresh lemon juice until smooth. Drizzle the glaze over the bread before slicing.