Preheat the oven to 350°F.
Spray a large bundt pan with non-stick cooking spray and set aside
In a large mixing bowl add the flour, sugar, baking soda and salt. Stir until mixed.
Then add the milk, olive oil, applesauce, vinegar, vanilla, lemon juice and lemon zest. Whisk by hand until combined and no big lumps remain. Be careful not to over mix.
Pour the batter into the prepared pan and back for 30 minutes or until a toothpick inserted into the center of the cake comes out clean.
Remove the oven and invert the cake onto a wire cooling rack to cool completely before frosting.
In a large bowl, add the powdered sugar, butter and lemon juice. Start off at slow speed, gradually increasing speed until thick and smooth.
Frost the cooled cake.
Note to lemon lovers: The lemon flavor is subtle in this cake. If you want more lemony flavor, add 1 or 2 teaspoons of lemon extract to the batter.