Preheat the oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.
In a medium bowl, whisk together the all-purpose flour, baking powder, and salt. Set aside.
In a large bowl, using an electric mixer, cream the softened butter and granulated sugar together until light and fluffy, about 3-4 minutes.
Add the eggs one at a time, beating well after each addition.
Mix in the vanilla extract, lemon juice, and lemon zest until combined.
Alternately add the flour mixture and milk to the butter mixture, beginning and ending with the flour mixture. Mix each addition just until incorporated.
Fold in the sour cream gently until fully combined.
Divide the batter evenly between the prepared cake pans and smooth the tops with a spatula.
Bake for 32-35 minutes, or until a toothpick inserted into the center of the cakes comes out clean.
Remove the cakes from the oven and let them cool in the pans for 10 minutes.
Run a knife around the edges and turn the cakes out onto wire racks to cool completely.
To prepare the lemon glaze, whisk together the powdered sugar, lemon juice, and lemon zest in a small bowl until smooth.
Once the cakes are completely cool, place one cake layer on a serving plate and spread a thin layer of glaze on top.
Place the second cake layer on top and pour the remaining glaze over the top, allowing it to drip down the sides.
Let the glaze set for about 15 minutes before slicing and serving.