Preheat your oven to 350°F (175°C). Grease and flour a cake pan.
In a mixing bowl, cream together the butter and sugar until light and fluffy.
Add the eggs one at a time, beating well after each addition.
In another bowl, combine the flour, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, alternating with the milk. Mix until just combined.
Stir in the lemon juice and lemon zest.
Pour the batter into the prepared cake pan and smooth the top.
Bake for 30 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cake to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.