Preparation: Preheat your oven to 350°F (175°C) and grease a 9-inch round cake pan or loaf pan. Line the bottom with parchment paper for easy removal.

Dry Ingredients: In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.

Wet Ingredients: In a large mixing bowl, cream the softened butter and sugar together using an electric mixer until light and fluffy, about 2-3 minutes. Add the eggs one at a time, mixing well after each addition. Stir in the lemon zest and vanilla extract.

Combine: In a small bowl, whisk together the lemon juice, milk, and sour cream. Gradually add the dry ingredients to the butter mixture, alternating with the milk mixture. Begin and end with the dry ingredients, mixing until just combined. Avoid overmixing.

Bake: Pour the batter into the prepared pan and smooth the top. Bake for 35-40 minutes (for a round cake) or 50-55 minutes (for a loaf), or until a toothpick inserted in the center comes out clean.

Cool: Allow the cake to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.

Lemon Glaze: In a small bowl, whisk together powdered sugar and lemon juice until smooth. Adjust the consistency with more lemon juice or powdered sugar, as needed. Drizzle the glaze over the cooled cake and sprinkle with extra lemon zest if desired.