Preheat oven to 350° F. Line three 6-inch round cake pans with parchment paper. Lightly grease and set aside.
In a large bowl, whisk together flour, baking soda, and salt. Set aside.
In the bowl of a stand mixer fitted with a paddle attachment, cream butter. Add sugar and lemon zest whip until smooth. Add eggs and continue to mix on medium speed until incorporated. Scrape down bowl as needed to ensure thorough mixing.
Mix milk and lemon juice together. Set aside. Add flour mixture in three additions, alternating with sour milk mixture. Begin and finish with flour mixture. Mix until well incorporated.
Divide batter evenly among the three prepared cake pans. Level batter using a mini offset spatula, or the back of a spoon. Bake for 35-40 minutes until a toothpick inserted in center of cake comes out clean. Let cake cool in pan for 5 minutes, then run a mini offset spatula around the cake and unmold. Let cake cool to room temperature on wire rack.