Preheat your oven to 350°F and prepare a 9-inch loaf pan by greasing it and lining with parchment paper. Make sure the parchment extends on two sides for easy removal later.
In a large mixing bowl, whisk together the flour, baking powder, baking soda, and salt.
In another bowl, combine the granulated sugar and lemon zest. Rub the zest into the sugar with your fingertips until the mixture is fragrant and turns light yellow.
Whisk the melted butter into the sugar, then beat in the eggs one at a time. Follow with the buttermilk and lemon extract, whisking until smooth.
Gradually fold the dry ingredients into the wet mixture using a spatula, mixing just until combined. Avoid overmixing to keep the bread tender.
Pour the batter into the prepared loaf pan and smooth the top evenly. Bake for 53-55 minutes, or until the top springs back when touched and a toothpick inserted in the center comes out clean.
Let the bread cool in the pan for 30 minutes. Run a knife around the edges, then gently invert the loaf onto a cooling rack to cool completely.
While the bread cools, make the glaze. Stir together powdered sugar and lemon juice in a small bowl until smooth. Adjust consistency with more sugar or lemon juice as needed.
Drizzle the glaze over the cooled bread using a fork, or spread it for a thicker, more uniform coating.