Preheat the oven to 350°F (177°C), and then grease a loaf pan with cooking spray or line it with parchment paper and set aside.
Beat butter and sugar together with a mixer until creamy. Add eggs then sour cream and lemon extract and mix thoroughly.
Slowly mix in flour, baking powder, baking soda, salt and lemon zest until just incorporated.
Pour half the batter into the prepared loaf pan and bake in the oven at 350°F (177°C) for 60 minutes or until a knife or toothpick comes out clean. Remove from the oven and allow to cool.
Mix together the powdered sugar, milk and lemon juice until smooth.
When the lemon loaf cake has cooled, drizzle over top and serve.