Preheat the oven to 350℉. Spray an 8-inch loaf pan with nonstick spray.
In a small bowl, sift together the flour, baking powder and salt. Set aside.
In a large bowl, use an electric mixer to cream the sugar and butter together for about 2 full minutes. Then mix in the eggs.
Mix in half of the dry ingredients, then mix in the sour cream. Then mix in the rest of the dry ingredients as well as the lemon zest, lemon juice and lemon extract.
Scrape the batter into the prepared pan. Bake for 50 minutes, or until a toothpick inserted into the center comes out clean. Remove the pan from the oven, and let it cool for 15 minutes. Then turn the lemon loaf out onto a cooling rack. Let the loaf cool completely.
PREPARE THE GLAZE:
In a medium bowl, whisk together the powdered sugar and lemon juice. Drizzle the glaze on top of the loaf. Let it drip down the sides, as needed. Let the glaze harden, and then slice and serve.