Preheat the Oven: Set your oven to 350°F (175°C). Grease and flour a 9×5-inch loaf pan or line it with parchment paper for easy removal.
Mix Dry Ingredients: In a medium bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt.
Prepare Wet Ingredients: In a large mixing bowl, whisk the eggs, sugar, and sour cream until smooth and creamy. Slowly add the vegetable oil, whisking continuously. Stir in the lemon zest, fresh lemon juice, vanilla extract, and lemon extract (if using).
Combine Wet and Dry Ingredients: Gradually fold the dry ingredients into the wet mixture. Stir gently until no lumps remain.
Bake the Lemon Loaf: Pour the batter into the prepared loaf pan and bake for 50–55 minutes, or until a toothpick inserted into the center comes out clean.
Cool the Loaf: Remove the loaf from the oven and let it cool in the pan for 10 minutes. Then, transfer it to a wire rack to cool completely.
Prepare the Lemon Glaze: In a small bowl, whisk together the powdered sugar and fresh lemon juice until smooth. Adjust consistency with milk if needed.
Glaze the Loaf: Once the loaf is completely cooled, drizzle the glaze over the top and let it set before slicing.