Preheat oven to 350 F. Grease and flour a 9x5 inch loaf pan.
In a large bowl whisk egg, sour cream, sugar, and oil until well combined. Stir in lemon zest, and lemon extract.
Add flour, baking powder, and salt, then stir until just combined.
Bake for 50-52 minutes, or until a tooth pick inserted in the center comes out clean.
If needed: Loosely cover the pan with foil during the last 10-15 minutes of baking to prevent excess browning around the edges.
Cool in pan for 25-30 minutes.
For the Glaze
In a medium bowl, combine powdered sugar, and lemon juice until smooth. Add more lemon juice or a bit of milk if needed to reach your desired consistency.